Build 9540 connectivity problems - DO NOT UPGRADE! (Build 9543 is ok)

Sébastien Riccio Replied

Yesterday at 3:56 AM

Same here pfff.

Upgraded to 9540 yesterday, and this morning MANY calls and tickets about connectivity issue.

So in emergency, I uninstalled 9540, re-installed 9526 but the service won't start.

I see in windows application event viewer, when 9526 tries to start:

"Version downgrade is not possible with this version of SmarterMail. Please run a newer version."

Incredible !!!!!!!!!!!!!!

I had to reinstall 9540 to have the service to start, but I'm not sure the connectivity/timeouts issue will be solved.

Sébastien Riccio System & Network Admin https://swisscenter.com

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Charalampos Michael Replied

Yesterday at 4:04 AM

They NOT! i did noumerous times! Somebody do emergecy ticket to smartertools ... i am still investigating .... Trying to restore from backup ... i hope 9540 does not corrupt data folders

Sébastien Riccio Replied

Yesterday at 4:08 AM

I noticed that the timeouts our customers are getting are maybe due to an unexpected amount of IDS triggered.

I usually have around 10-15 IP's blocked (mostly foreign country).

But with 9540 the IDS DDoS protection is blocking our customer IP addresses and a lot of them !

I removed the IDS rule to see if it helps running 9540 correctly ...

Sébastien Riccio System & Network Admin https://swisscenter.com

Sébastien Riccio Replied

Yesterday at 4:18 AM

Interresting, when a user succesfully logs in, it adds it's IP to DoS blacklist:

[2026.02.16] 09:10:51.833 [a.b.c.d] IMAP Login successful: With user someuser@somedomain.ch
[2026.02.16] 09:11:30.731 [a.b.c.d] IMAP Attempting to login user: somedomain@somedomain.ch
[2026.02.16] 09:11:30.731 [a.b.c.d] IMAP Login successful: With user somedomain@somedomain.ch
[2026.02.16] 09:13:51.586 [a.b.c.d] SMTP Login successful: For user somedomain@somedomain.ch
[2026.02.16] 09:15:40.638 DenialOfService [DenialOfService a.b.c.d] Added IP to IDS block list. Duration: 1799,9979497 seconds, Description: Default DoS rule
[2026.02.16] 09:46:17.667 [a.b.c.d] IMAP Attempting to login user: somedomain@somedomain.ch
[2026.02.16] 09:46:17.667 [a.b.c.d] IMAP Login successful: With user somedomain@somedomain.ch
[2026.02.16] 09:48:05.268 DenialOfService [DenialOfService a.b.c.d] Added IP to IDS block list. Duration: 1799,9977592 seconds, Description: Default DoS rule
[2026.02.16] 10:22:15.481 [a.b.c.d] IMAP Attempting to login user: somedomain@somedomain.ch
[2026.02.16] 10:22:15.481 [a.b.c.d] IMAP Login successful: With user somedomain@somedomain.ch
[2026.02.16] 10:23:59.139  DenialOfService [DenialOfService a.b.c.d] Added IP to IDS block list. Duration: 1799,9978737 seconds, Description: Default DoS rule
[2026.02.16] 10:54:25.865 [a.b.c.d] IMAP Attempting to login user: someuser@somedomain.ch
[2026.02.16] 10:54:25.865 [a.b.c.d] IMAP Login successful: With user someuser@somedomain.ch
[2026.02.16] 10:54:45.461 [a.b.c.d] IMAP Attempting to login user: someuser@somedomain.ch

Sébastien Riccio System & Network Admin https://swisscenter.com

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Charalampos Michael Replied

Yesterday at 4:19 AM

Even if you whitelist his IP, i wonder if we can disable IDS for the moment.

Sébastien Riccio Replied

Yesterday at 4:42 AM

I removed the IDS rule for DDoS (there is no way to disable it, only delete) and removed all blacklisted IPs.

We're waiting for customer feedback...

Sébastien Riccio System & Network Admin https://swisscenter.com

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Charalampos Michael Replied

Yesterday at 5:08 AM

i did that nothing changed

C

Charalampos Michael Replied

Yesterday at 5:57 AM

seems binding problerms ... i regenerated the SSL nothing.

14:52:03.157 System.Threading.Tasks.TaskCanceledException: A task was canceled.
at SmarterMail.Protocols.Common.PooledTcpServer.Listener()
14:52:13.418 [fe80::a1f8:e2b7:622b:f07c%3:993] Binding(2) Exception: System.Net.Sockets.SocketException (10049): The requested address is not valid in its context.
at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, Boolean disconnectOnFailure, String callerName)
at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Bind(EndPoint localEP)
at SmarterMail.Protocols.Common.PooledTcpServer.StartListening(IPEndPoint a, db_system_binding_port b)
14:53:27.959 System.Threading.Tasks.TaskCanceledException: A task was canceled.
at SmarterMail.Protocols.Common.PooledTcpServer.Listener()
14:53:39.082 [fe80::a1f8:e2b7:622b:f07c%3:993] Binding(2) Exception: System.Net.Sockets.SocketException (10049): The requested address is not valid in its context.
at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, Boolean disconnectOnFailure, String callerName)
at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
at System.Net.Sockets.Socket.Bind(EndPoint localEP)
at SmarterMail.Protocols.Common.PooledTcpServer.StartListening(IPEndPoint a, db_system_binding_port b)

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Christian Schmit Replied

Yesterday at 6:03 AM

Same here. We have temporarily deleted the IDS DDoS protection rule for now.

B

Bruce Replied

Yesterday at 6:06 AM

We encountered the DoS issue immediately on Saturday and had to delete the rule. However, we are now also receiving reports about IMAP connectivity problems.

J

J. LaDow Replied

Yesterday at 6:14 AM

@Charalampos Michael:

Addresses with fe80: prefix are link-local addresses in Windows servers -- on our server (9526 and for the two years prior on our previous build) - we've never bound SM ports/protocols to link-local.

Try only binding to your localhost (127.0.0.1 / 0::) and your public / "actual" internal IPs and see what happens --

RE: IDS changes:

Additionally, we had noticed a behavior change when landing on 9526 with IDS and NTLM that was adding IDS entries before throttling with IMAP connections kicked in - and was causing users who previously never had issues. We were told that IDS logic was added between our old version (8657) and the 9526, but our old version had IDS on IMAP, would catch bad NTLM inputs and not add them to the IDS to the point where users were getting locked out with successful logins. That is a different issue, but still a problem none the less.

MailEnable survivor / convert --

C

Charalampos Michael Replied

Yesterday at 6:34 AM

1) Regenerated Let's Crypt SSL -> Nothing
2) Reset banding to None and the again to SSL -> Some clients connect
3) Tried unencrypted connection nothing.

So something is blocking the connection

Now i get these so i guess they have problems with their code guys, you can't fix it unless they publish an update! The sad thing is that you can't revert to old builds with service is crashing!

[2026.02.16] 15:11:59.214 [IP Unknown][11952267][993] Could not negotiate SSL session: Received an unexpected EOF or 0 bytes from the transport stream.
[2026.02.16] 15:16:49.458 [IP Unknown][1088956][993] Could not negotiate SSL session: Received an unexpected EOF or 0 bytes from the transport stream.
[2026.02.16] 15:18:58.931 [IP Unknown][8420316][993] Could not negotiate SSL session: Received an unexpected EOF or 0 bytes from the transport stream.
[2026.02.16] 15:19:25.465 System.Threading.Tasks.TaskCanceledException: A task was canceled.
[2026.02.16] at SmarterMail.Protocols.Common.PooledTcpServer.Listener()
[2026.02.16] 15:19:34.787 [fe80::a1f8:e2b7:622b:f07c%3:993] Binding(2) Exception: System.Net.Sockets.SocketException (10049): The requested address is not valid in its context.
[2026.02.16] at System.Net.Sockets.Socket.UpdateStatusAfterSocketErrorAndThrowException(SocketError error, Boolean disconnectOnFailure, String callerName)
[2026.02.16] at System.Net.Sockets.Socket.DoBind(EndPoint endPointSnapshot, SocketAddress socketAddress)
[2026.02.16] at System.Net.Sockets.Socket.Bind(EndPoint localEP)
[2026.02.16] at SmarterMail.Protocols.Common.PooledTcpServer.StartListening(IPEndPoint a, db_system_binding_port b)
[2026.02.16] 15:19:51.820 [IP Unknown][61909267][993] Could not negotiate SSL session: Received an unexpected EOF or 0 bytes from the transport stream.
[2026.02.16] 15:20:27.459 [IP Unknown][62710127][993] Could not negotiate SSL session: Received an unexpected EOF or 0 bytes from the transport stream.

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Tan Replied

Yesterday at 6:51 AM

I have 2 user reporting email sent but not saved inside the sent folder. Today is technically non working day due to upcoming public holiday

Anyone else has such report? I suspect could it be due to ddos too?

B

Bruce Replied

Yesterday at 6:59 AM

IMAP issue looks to be related to these log entries

[2026.02.16] 11:22:17.764 [RemovedIP][15850611] command: A16 APPEND "Sent Items" (\Seen) "16-Feb-2026 11:22:10 +0000" {304499}

[2026.02.16] 11:22:17.764 [RemovedIP][15850611] response: + Ready for additional command text

[2026.02.16] 11:22:18.374 [RemovedIP][15850611] Command line exceeds maximum length (16788)

[2026.02.16] 11:22:18.374 [RemovedIP][15850611] disconnected at 16/02/2026 11:22:18

I am seeing lots of these

Command line exceeds maximum length (16788)

Didn't have them prior to the latest version

C

Charalampos Michael Replied

Yesterday at 7:00 AM

emclient log says the server is closing the connection!

15:58:17.017|01A| eM Client 10.4.4209+d96494be7c (Windows)
15:58:17.023|02B| Account's UID is 7b4ef3e4-0672-4241-b165-cf85f282e93f
15:58:17.024|02B| AccountBase.ChangeOnlineState : State changed to ONLINE due User
15:58:17.024|02B| AP: Avoid SEARCH by MessageId
15:58:17.030|02B| >>> FolderActivated(folder: /Inbox [Inbox]):
15:58:17.030|02B| Folder /Inbox [Inbox] is now watched
15:58:17.056|02B| >>> FolderActivated(folder: /Inbox [Inbox]):
15:58:17.064|02B| >>> UploadAsync(folder: /Drafts [Draft]): Start
15:58:17.068|02B| >>> Starting account synchronization
15:58:17.088|02B| >>> AppendAsync(folder: /Drafts [Draft], item: emc3fedd4b-2962-4684-9ca5-b7b1d16a4ae2@myserver.com): Start
15:58:17.125|02B| 01: Connecting to mail.office.myserver.com:993 with TLS ...
15:58:17.136|02B| 01: TLS stream established with Protocol: Tls13, NegotiatedCipherSuite: TLS_AES_256_GCM_SHA384, CipherAlgorithm: Aes256, HashAlgorithm: Sha384
15:58:17.190|02B| 01: * OK IMAP4rev1 SmarterMail
15:58:17.216|02B| 01: A1 CAPABILITY
15:58:17.218|02B| 01: * CAPABILITY IMAP4rev1 AUTH=CRAM-MD5 AUTH=NTLM AUTH=PLAIN SASL-IR UTF8=ACCEPT UIDPLUS QUOTA MOVE XLIST CHILDREN ENABLE CONDSTORE X-SM-TAGS IDLE
15:58:17.263|02B| 01: A1 OK CAPABILITY completed
15:58:17.278|02B| 01: A2 AUTHENTICATE CRAM-MD5
15:58:17.279|02B| 01: + <Parameter removed for privacy reasons.>
15:58:17.284|02B| 01: <Parameter removed for privacy reasons.>
15:58:17.286|02B| 01: A2 OK [CAPABILITY IMAP4rev1 AUTH=CRAM-MD5 AUTH=NTLM AUTH=PLAIN SASL-IR UTF8=ACCEPT UIDPLUS QUOTA MOVE XLIST CHILDREN ENABLE CONDSTORE X-SM-TAGS IDLE] CRAM authentication successful
15:58:17.288|02B| 01: Detected server type: SmarterMail
15:58:17.288|02B| 01: A3 ENABLE CONDSTORE
15:58:17.289|02B| 01: * ENABLED CONDSTORE
15:58:17.340|02B| 01: A3 OK ENABLE completed
15:58:17.362|02B| 01: A4 SELECT "Drafts" (CONDSTORE)
15:58:17.363|02B| 01: * 1 EXISTS
15:58:17.418|02B| 01: * 0 RECENT
15:58:17.419|02B| 01: * OK [UIDVALIDITY 1] UIDs valid
15:58:17.420|02B| 01: * OK [UIDNEXT 11035] Predicted next UID
15:58:17.420|02B| 01: * OK [HIGHESTMODSEQ 16695230988290] Mod sequence
15:58:17.420|02B| 01: * FLAGS (\Answered \Flagged \Deleted \Seen \Draft \Recent)
15:58:17.421|02B| 01: * OK [PERMANENTFLAGS (\Answered \Flagged \Deleted \Seen \Draft \Recent \*)] Folder flags
15:58:17.421|02B| 01: A4 OK [READ-WRITE] SELECT completed, CONDSTORE enabled
15:58:17.446|02B| >>> DoAppendAsync(folder: /Drafts [Draft], item: emc3fedd4b-2962-4684-9ca5-b7b1d16a4ae2@myserver.com): Start
15:58:17.461|02B| 01: A5 APPEND "Drafts" (\Seen \Draft) "16-Feb-2026 11:03:31 +0000" {38273}
15:58:17.464|02B| 01: + Ready for additional command text
15:58:17.469|02B| 01: --- literal uploaded (38273B)
15:58:17.469|02B| 01: --- \r\n (out)
15:58:17.471|02B| 01: --- RECEIVE: CONNECTION LOST
15:58:17.472|02B| 01: --- RECEIVE: SAYING CONNECTION LOST TO CMD A5
15:58:17.472|02B| 01: --- RECEIVE: CLOSED
15:58:17.473|02B| 01: --- CMD A5 APPEND FAILED: Lost connection with server
15:58:17.478|02B| >>> COMMAND CONNECTION EXCEPTION (retry: True): Lost connection with server
15:58:17.478|02B| >>> UploadAsync(folder: /Drafts [Draft]): Start

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Charalampos Michael Replied

Yesterday at 7:01 AM

@J. LaDow nope it's not that. seems it does not clear IDS blacklists or something ....

Richard Laliberte Replied

Yesterday at 7:12 AM

Any word on a custom build coming that might fix this? We don't have access to the ticket systems unfortunately only our provider does, and i have to pretty much tell them when to update lol

C

Charalampos Michael Replied

Yesterday at 7:18 AM

i did submit a ticket, i guess they are sleeping at USA now

T

Tan Replied

Yesterday at 7:24 AM

I just checked further, i think this build is confirmed having problem. I checked on the user that reported the issue to us, indeed their sent item was not having any new email recorded, I checked our outboud gateway and there is email sending out by the user

C

Charalampos Michael Replied

Yesterday at 7:36 AM

@Tan as you can see i have the same problem on several installations and other people have the same issue, so it's a non-production build. Some "change" from the below screw it up i guess ... I upgraded because i saw the "IMPORTANT: [SECURITY]"

Security: Added access restrictions to a system with compromised RSA key.
Security: Added the ability for system administrators to add IP restrictions for all APIs.
Security: APIs now follow blacklist/whitelist restrictions for all scope levels.
Security: Hardened various protocols against complex memory exhaustion issues.
Security: Hardened various syncing protocols against complex entity expansion issues.

D

Dave Replied

Yesterday at 7:42 AM

Yeah seeing a lot of Command line exceeds maximum length issues.

Richard Laliberte Replied

Yesterday at 7:43 AM

well i know they aren't sleeping, because i saw Derek comment on one of the other threads. so they are probably franticly looking into this. Luckily it's a holiday here, so our clients are mostly out of the office today so hopefully a patch by tonight lol

C

Charalampos Michael Replied

Yesterday at 7:44 AM

You're lucky richard, i had many tickets and calls from bosses too ...

I hope they fix it today else will kill us all! lmao

@SMARTERTOOLS
You must find a way to downgrade always! You won't get fired if the e-mail server does not work! Yes i know you're upgrading file structures but for this kind critical work application we can't have too many hours of downtime!

Thank you

N

Nathan Replied

Yesterday at 7:45 AM

IP Blocking encountered here with the 9540 build when it has never been an issue before. I have deleted the DDOS rule as others suggested and monitoring if this is a workaround. We are running under Debian 12.

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Charalampos Michael Replied

Yesterday at 7:46 AM

Deleting the IDS rules makes not difference .... It still blocks/unblocks connections randomly

Richard Laliberte Replied

Yesterday at 7:53 AM

I thought i remember reading in one of the threads somewhere that the downgrade issue was the result of changes to command line usage, and someone posted a fix but i can't seem to find it right now as most threads are getting VERY long lol.

T

Tan Replied

Yesterday at 7:54 AM

@Charalampos Michael, yes i saw security updates so i had to urgently upgrading the build otherwise i usually wait for 3-4 weeks to update for the dust to settle down.

Luckily it is public holiday tomorrow otherwise i cant imagine the call. But we have to have this fix ASAP as those user working today didnt have the email saved in sent items.

D

Dave Replied

Yesterday at 8:01 AM

@ Richard Laliberte

It's in here.

https://portal.smartertools.com/community/a97778/build-9540-information.aspx

If it is necessary to downgrade SmarterMail, for whatever reason, system administrators can review the Administrative logs to find the command lines that were converted so that they can re-apply the settings. Alternatively, they can restore files from the most recent Archived Data folder as detailed in our Backup and Restore SmarterMail knowledge base article.

T

Tan Replied

Yesterday at 8:03 AM

Let's hope for a patch soon otherwise downgrade might be a disaster too.

d

digital.iway Replied

Yesterday at 8:05 AM

We are also experiencing this same IMAP sync issue and seeing many IMAP log entries with (Command line exceeds maximum length (17884)). We removed the IDS DOS rule for now hoping that will help at least get users mail to the inbox for those that seem to be blocked. We opened a ticket about an hour ago and no response yet. my concern is when they fix this will all syncing start working or will we all be out of sync forever in outlook / emclient / other.

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Charalampos Michael Replied

Yesterday at 8:06 AM

@Dave, @Derek (Smartertools)

This is not acceptable, The installer should backup those changes in case we need to downgrade so we can revert back and downgrade in minutes not hours!

Tip to SmarterTools tell Claude AI to make you a revert script for the installer .... You'll have it in an hour ready!

or

make a backup of the previous installation in a "Backup" folder and add the ability to the installer to revert back so everybody will be happy!

New build problems ? Installer -> Revert back to previous build ... at least microsoft is doing something right with uninstalling broken windows updates lmao ...

Thank you

C

Charalampos Michael Replied

Yesterday at 8:14 AM

The easy way for a fix this TODAY to remove the new code they added to fix those security issues ...

Have a beta build, test it well and add it back fixed

J

J. LaDow Replied

Yesterday at 8:14 AM

I personally don't want AI dictating any coding regarding SmarterMail. They're having enough problems doing it with human eyes - AI is not the solution (and I personally can't wait until that bubble explodes). AI is good at researching and building datasets, then analyzing that data - but that's it. It cannot "think" or "reason" and for that alone shouldn't be making "decisions" in any fashion. Just my two cents.

Regarding the rest of your thoughts, yes the installer could do more regarding data safety during upgrades, but in context, most sysadmins take snapshots at least of settings files and folders prior to uninstalling and running the upgrade. We shouldn't have to, but SmarterTools isn't the only company who's had bad updates - and that experience alone means we (at least me) apply the same logic across the board. On top of all that - it is generally known (at least on the forums) that most admins do an uninstall of SmarterMail between upgrades, as this has proven to be an issue in the past. At this juncture is also a good time to take a snapshot of "what's left" in the SmarterMail folder (this at least captures the main settings files). We wrote a script that gathers ALL the xml, sbin, and json files SM uses and makes a mirror of them in a separate folder just in case of catastrophe (but we learned this lesson with MailEnable, and have just applied it forward)...

That said, detailed rollback instructions should be available. SmarterTools development cycle has accelerated so much that documentation and KB articles aren't keeping up. This includes documenting changes/necessary parameters for API usage.

MailEnable survivor / convert --

Richard Laliberte Replied

Yesterday at 8:25 AM

Smartertools has stated publicly they are doing many security audits and upgrades and fixes right now. i know it's a real pain sometimes, but at least they are doing the fixes, and the product that comes out at the end of all this will "hopefully" be rock solid in terms of security. And with so many countries looking for alternatives to MS for email, this is a perfect time for them to make these upgrades.

So i for one, although a bit annoyed when we have issues like this, am thankful they are doing this, and I will do my part reporting any issues that come up during any upgrades ASAP so that the team can fix the issues

C

Christian Schmit Replied

Yesterday at 8:29 AM

We also see IMAP sync problems. Several IMAP customers reporting that sent emails are not being saved in their Sent folder.

J

Jay Dubb Replied

Yesterday at 8:30 AM

We're happy with the increased focus on security, but are not celebrating because diligent security should have been the process all along. Flaws happen, that's understandable, but some of these have been glaring, like unauthenticated users being able to force-reset admin passwords. It's unfortunate that it took some serious CVE activity to bubble all of this to the surface.

YS Tech Replied

Yesterday at 8:38 AM

I'm currently waiting for a fix before I upgrade, was going to last night as I saw the "Urgent" and had the email, but looking at the comments glad i held out. Hopefully it's still fairly secure without the current update!?!

C

Charalampos Michael Replied

Yesterday at 8:40 AM

J. LaDow

Well AI will help them not make production code of course, it's doing mistakes. (they have ate me alot of token for fix it's own mistakes lol)

As far for installer backuping up i meant the whole installation not only the settings (including the application) so it will be a simple revert back and use a script if data files are modified.

Since they're using windows installer it shouldn't be that hard.
Since the product is almost very good for everybody needs they can focus a bit time on the installer.

J

J. LaDow Replied

Yesterday at 8:41 AM

@YS Tech

One of the updates makes the IP restrictions you define on user accounts apply to the API - so apparently that wasn't a thing until 9540. That seems big if you ask me - considering like everything related to actually "operating" SmarterMail is built around the API...

We updated (because "CRITICAL"), ran our tests before enabling communications with the outside world - and saw issues immediately piling up in the logs with our tests. We were able to roll everything back but only because of how we back things up (noted above).

MailEnable survivor / convert --

D

Dave Replied

Yesterday at 8:43 AM

Has anyone heard back from tickets they opened yet?

Would open one of my own but seems redundant at this point.....

C

Charalampos Michael Replied

Yesterday at 8:45 AM

@J. LaDow again it's nothing for them to make it easy for us
@Dave i have made one ticket

Sébastien Riccio Replied

Yesterday at 8:49 AM

If it is necessary to downgrade SmarterMail, for whatever reason, system administrators can review the Administrative logs to find the command lines that were converted so that they can re-apply the settings. Alternatively, they can restore files from the most recent Archived Data folder as detailed in our Backup and Restore SmarterMail knowledge base article.

- What should we search in administrative logs ?

- Which files to restore for archived data folder ? System only files ? Domain/users data ?

Damn I just want to be able to revert to previous build and that it starts !!!!

Sébastien Riccio System & Network Admin https://swisscenter.com

Richard Laliberte Replied

Yesterday at 8:50 AM

Dave might as well open a ticket as well. the more tickets they see with the exact same issue the faster it will get fixed. my guess is since no one has responded yet to this thread that they are actively working on it though.

Just curious though, since they put in new command line features, and new IP lockdown stuff, has anyone seen the issue pop up more with larger offices that might all be behind 1 IP address vs individual users on different IP addresses? Maybe we will get lucky and they just over tightened the rule saying how many logins from a specific IP address? lol

T

Tan Replied

Yesterday at 8:53 AM

They did reply to my ticket. I point them over here as they are trying to gather more information but i think they are trying to narrow down the issue too.

Maybe when they read here they will understand a simple imap sent email unable to save email might be easy for them to backtrace their code to see what happen

C

Charalampos Michael Replied

Yesterday at 8:59 AM

@Sébastien Riccio Extactly that's why i am requsting to add the ability to revert in the installer!

C

Charalampos Michael Replied

Yesterday at 9:01 AM

I guess the bug it's a simple "IF" condition ... IF build 9540 then Block them all! <g>

Sébastien Riccio Replied

Yesterday at 9:14 AM

I think I finally was able to re-install previous build.

1) Stopped smartermail service (and waited that the mailservice.exe is really gone from running processes)

2) Uninstalled build 9540 using the 9540 installer

3) Extracted the content of
C:\Program Files (x86)\SmarterTools\SmarterMail\Service\Settings\Archived Data\system-2026-02-15.zip
to
C:\Program Files (x86)\SmarterTools\SmarterMail\Service\Settings

4) Installed previous build 9526

This time the previous build DID start without mailservice.exe complaining "Version downgrade is not possible with this version of SmarterMail. Please run a newer version." in the windows event viewer.

I hope this will fix the issues brought by 9540 as our customers are close to set our office on fire.

Sébastien Riccio System & Network Admin https://swisscenter.com

d

digital.iway Replied

Yesterday at 9:52 AM

I did not hear anything back on my ticket.

strange thing to note about this was: IMAP did sync for for fine when I tested this morning without attachment, BUT started to fail ONLY when I tested with attachments.

Sequence: After trying to send the first test email with outlook (including an attachment) it seemed to sync that first test, but webmail did not show the attachment in the email. The second oultlook test after that with an attachment again did not even sync to webmail at all and sent items along with deleted items stopped syncing. I could be wrong on this BUT It seems that once you attempt an attachment email once with outlook IMAP then all sent and deleted email fails to sync after that and IMAP is in a partially failed state / crash.

G

George Replied

Yesterday at 10:00 AM

Hello,

I have received a response to my ticket regarding the IMAP issue. The response arrived quite quickly. I sent it less than an hour ago.

----------------------------------------------

Hello,

Our development team is aware of this and are actively working to fix this issue. I will leave this ticket open to keep you updated on its status.

Thank you,

B

Bruce Replied

Yesterday at 10:00 AM

If you look in your IMAP logs you will see this;

Command line exceeds maximum length (number here)

The IMAP connection is closed once the email reaches a certain size, so anything with images and attachments will cause the connection to close.

C

Charalampos Michael Replied

Yesterday at 10:16 AM

@George, nice! i hope we have a fix today

D

Dave Replied

Yesterday at 10:23 AM

Got the same response to my ticket. More to just get a notification when it's released.

Derek Curtis Replied

Yesterday at 10:35 AM

Employee Post

Just a note. As a few of you have noted, we've identified the issues and will have a fix out later this afternoon.

The IMAP issue is only affecting messages sent that are larger than a specific size. This can be due to the message itself, or messages with large attachments. That, then, can cause the IDS blocks as the sender hits the server as it repeatedly tries sending these messages.

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

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Tan Replied

Yesterday at 10:40 AM

Thanks. Any idea what specific size as i have client sent item has no new email for past few days even their email content is small

Richard Laliberte Replied

Yesterday at 10:43 AM

I think an important question at this point would be, will be at some point in the future have the ability to set that message size limit ourselves? Either by server wide, domain wide or at the specific user level?

Sébastien Riccio Replied

Yesterday at 11:00 AM

Well, if limiting the message size results in having mail clients completely stuck, when it tries to save an overlimit item on the IMAP sent item folders, I'm not sure that's the greatest idea.

Where do this 16788 limit comes from ? Is it bytes, megabytes ? Huh

EDIT: Asking AI about it:

The number 16788 lacks a single definitive meaning and appears in various contexts like numerology, science, and technical catalogs.

Numerology and Angel Numbers

In numerology, numbers close to 16788 (like 1678) symbolize transformation, inception, mastery, creativity, emotional support, and achievement. Angel number interpretations for 1678 or similar suggest manifesting desires, spiritual awakening, leadership, abundance, and biblical ties to creation and completeness.

Scientific References

NWA 16788 designates a Martian shergottite meteorite found in Niger in 2023, weighing about 24.67 kg—the largest known Martian meteorite on Earth, recently auctioned for millions.

Technical Codes

It appears as ORA-16788, an Oracle Data Guard broker error for failing to set database properties like ApplyInstances. Other uses include a LOINC medical code for dopamine measurement in urine and product identifiers like a catalytic converter part.

Ok now makes sense :)))

Sébastien Riccio System & Network Admin https://swisscenter.com

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Charalampos Michael Replied

Yesterday at 11:05 AM

I LOVE YOU @DEREK! That's why i love SmarterTOOLS! <3 ... Seems i won't get fired after all <vbg>

Please also provide us a step by step guide in case the fix also fails to revert back.

@derek please consider my installer requests in this thread

John C. Reid Replied

Yesterday at 11:32 AM

Just chiming in to say I am seeing the same issue on my Linux SmarterMail server after the upgrade. I have not fully read the thread yet, but the last reply from @Charalampos Michael has me hopeful there is a fix in there someplace.

John C. Reid / Technology Director John@prime42.net / (530) 691-0042 1300 West Street, Suite 206, Redding, CA 96001

Richard Laliberte Replied

Yesterday at 1:01 PM

Anyone get an update yet?

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Charalampos Michael Replied

Yesterday at 1:10 PM

I am watching https://www.smartertools.com/smartermail/downloads it's make sense to release it there.

Derek Curtis Replied

Yesterday at 1:34 PM

Employee Post

I'll post an update once a Build is available. To answer a few questions:

1. 16788 is in bytes.

2. Installer changes for roll backs is not a bad suggestion, so will be discussed.

3. Discussing that size setting as well -- whether to make it one or limit the implementation to just areas that won't affect sending/delivery.

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

Derek Curtis Replied

Yesterday at 1:53 PM

Employee Post

Sorry, but I missed Sebastien's questions a bit earlier. For anyone still wondering about the administrative logs displaying command lines that were converted, here's what an administrative log would look like:

[2026.02.12] 13:41:32.669 Created Scripts directory
[2026.02.12] 13:41:32.670 Migration: ACME original command: 'powershell.exe -command ""[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')] SM COMMAND LINE ACTION" | Out-File -FilePath "C:\CommandLineLogFile.txt" -Append -Encoding UTF8"', arguments: ''
[2026.02.12] 13:41:32.670 Created script: acmeRenewal.bat
[2026.02.12] 13:41:32.670 Migrated ACME script
[2026.02.12] 13:41:32.670 Migration: Antivirus original command: '"%ProgramFiles%\Windows Defender\MpCmdRun.exe" -Scan -ScanType 3'
[2026.02.12] 13:41:32.671 Created script: antiVirus.bat
[2026.02.12] 13:41:32.671 Migrated antivirus script
[2026.02.12] 13:41:32.671 Migration: Spool script original command: 'C:\SmarterMail\Spool-Script-CaptureEmlHdrFileDetails.cmd %filepath'
[2026.02.12] 13:41:32.671 Created script: spool.bat
[2026.02.12] 13:41:32.671 Migrated Spool script
[2026.02.12] 13:41:32.671 Migration: Mount 1 original command: 'net use Z: \\it-storage.st.local\staging /user:'
[2026.02.12] 13:41:32.673 Created script: mount-1.bat
[2026.02.12] 13:41:32.673 Migration: Unmount 1 original command: 'net use Z: /delete'
[2026.02.12] 13:41:32.674 Created script: unmount-1.bat
[2026.02.12] 13:41:32.674 Migrated 1 mount scripts
[2026.02.12] 13:41:32.685 Migration: Event 'Command Line Test' original command: 'powershell.exe', arguments: '"[$(Get-Date -Format 'yyyy-MM-dd HH:mm:ss')] SM COMMAND LINE ACTION" | Out-File -FilePath "C:\CommandLineLogFile.txt" -Append -Encoding UTF8'
[2026.02.12] 13:41:32.687 Created script: Command_Line_Test.bat
[2026.02.12] 13:41:32.687 Migrated 1 event scripts

Don't know if it will display, but the bolded areas are the actual command lines that were converted to scripts, and then the script name is on the next line. You can take that info and just paste it into the Command-Line Action on any reverted installation.

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

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Charalampos Michael Replied

Yesterday at 1:54 PM

Thank you @Derek ... Installer rollback to previous version will be the best thing ever for all of us!

Something went wrong with the current build ?
Run installer and rollbar to the previous working in just minutes.

No hurrying up to make any fixes, no angry customers or boss calls,
no major downtimes of e-mail server!

Everyone happy!

Thank you

Sébastien Riccio Replied

Yesterday at 2:11 PM

Thank you Derek.

Actually I don't think that the command line conversion was the issue for downgrading to previous build.

We had no particular command-line calls on our setup and I see no "Migration" entries in our Administrative logs at all.

To be able to run the previous build, I needed to restore settings from an "Archived data" zip file dated before the upgrade occured.

Without this the previous build would start mailservice.exe and emit a very disappointing: "Version downgrade is not possible with this version of SmarterMail. Please run a newer version." in the system event log.

Sébastien Riccio System & Network Admin https://swisscenter.com

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digital.iway Replied

Yesterday at 2:18 PM

Thank you @Derek - for planning purposes do you have any estimate / idea if this will be released in a hour, two hours or late tonight? I need to plan around our veeam backup auto run and determine if I do this before or after or change the auto run?

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Charalampos Michael Replied

Yesterday at 2:46 PM

@Derek
Well i have an 8 hours deadline here before everybody start working again in the morning ...

If it's not ready in 8 hours tell us step by step to rollback please!

I can install a custom build if you provide me the link too

Thank you

J

J. LaDow Replied

Yesterday at 3:14 PM

@sebastian detailed what he did to rollback in this post here: https://portal.smartertools.com/community/a97785/build-9540-connectivity-problems-do-not-upgrade.aspx#post152862 if that helps any. The key factor is to get the archive from before the upgrade to 9540. I would anticipate a build within the next couple hours -

MailEnable survivor / convert --

Derek Curtis Replied

Yesterday at 3:24 PM

Employee Post

The release should be available within the next 2 hours. We'll be using the max message size limitation that's already customizable versus any limit we set. Therefore, shouldn't be any need to roll back.

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

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russell lyon Replied

Yesterday at 3:34 PM

What time zone is this @ 15:24? We are also considering a rollback. We upgraded 15 mins after release on the 13th due to the IMPORTANT: [SECURITY] It's now been 3 days since we had issues.

From GMT

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digital.iway Replied

Yesterday at 3:42 PM

@ Derek can you please clarify max message size? max message size is set at the domain level and also global. I need to know what to make those settings because I think mine are wrong?

please clarify the difference between:
SMTP IN > MESSAGE LIMITS AND DELIVERY > MAX MESSAGE SIZE
AND
DOMAIN > OPTIONS MAX MESSAGE SIZE

Can you provide recommended settings for SMTP IN > MESSAGE LIMITS AND DELIVERY > MAX MESSAGE SIZE

Derek Curtis Replied

Yesterday at 3:42 PM

Employee Post

@russell -- we're GMT -7, so the release should be available around 17:00 MST (GMT -7)

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

Sébastien Riccio Replied

Yesterday at 3:49 PM

There still something I don't understand about the latest build issue with IMAP.

If it's an IMAP size limit issue, that has been introduced in latest build (can't find any entry about it in changelog btw):

If this size limit is reached, when trying to save a message on the server, through IMAP,it results in client being disconnected and then having timeouts, what will prevent this from happening again, whatever the size limit is set to ?

Will it now properly handle it and inform the mail client that the size limit is reached, instead of just disconnecting.
It looked to me that the mail clients were retrying indefinitely and therefore triggering the IDS DDoS stuff...

I try to understand what was the problem and how it was fixed. I'm not really confident to install the upcoming build after today's hell of a day I had with these issues.

Sébastien Riccio System & Network Admin https://swisscenter.com

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J. LaDow Replied

Yesterday at 3:50 PM

Most providers don't allow more than 10-15 meg attachments. We have an outbound gateway service that tops out at 50mb per message.

Your mileage may vary - inbound is at your own discretion - but seeing what most limits are, we went accordingly inbound and outbound -- 50mb (51200kb) on the SMTP-In, and just over 49mb (50000kb) on the Domain Defaults (which manages the outbound) -- FILE STORAGE limits are different settings entirely and rely on the web interface and are not protocol bound from what I understand.

MailEnable survivor / convert --

Sébastien Riccio Replied

Yesterday at 3:57 PM

Here the issue seems to be with IMAP message size limit when a message is saved through IMAP.
So I guess it is not linked to incoming SMTP messages site limit.

Then when a user submit a message with SMTP, there is a size limit too, for SMTP, will this same size be used as the limit to save a message through IMAP (into sent items folder for exemple?), or will it be configurable ?

What happens if a user create a message draft with 300MB attachments, but doesn't send it, only save it as a draft, it will then excess the limit... ?

Sébastien Riccio System & Network Admin https://swisscenter.com

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J. LaDow Replied

Yesterday at 3:59 PM

Because the "outgoing" message size is managed on a per-domain level - the assumption is that IMAP will adhere to this going forward from what Derek said.

This seemed to be a multi-part bug. I believe one part stems from a bad implementation (incomplete) of IMAP size limits to prevent some forms of DoS against the server with large uploads. The other part happens when a oversized-message is sent to the server, the server is supposed to gracefully reject the message. Here, SM is throwing an exception and crashing out the connection instead. The release should address both issues, at least --

MailEnable survivor / convert --

Sébastien Riccio Replied

Yesterday at 4:08 PM

Okay, I hope so :)

I tried to save a 250MB draft message from emclient on build 9526, seems it's handled gracefully.

Hopefully it will be in next release too :)

Sébastien Riccio System & Network Admin https://swisscenter.com

Derek Curtis Replied

Yesterday at 5:08 PM

Employee Post

Is that an IMAP mailbox or is it using EWS? The issue was only for IMAP-connected mailboxes.

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

Sébastien Riccio Replied

Yesterday at 5:19 PM

IMAP on build 9526

Sébastien Riccio System & Network Admin https://swisscenter.com

John C. Reid Replied

Yesterday at 5:47 PM

@Derek Curtis
> @russell -- we're GMT -7, so the release should be available around 17:00 MST (GMT -7)

Is my understanding of time zones wrong, or hasn't this already well past?

John C. Reid / Technology Director John@prime42.net / (530) 691-0042 1300 West Street, Suite 206, Redding, CA 96001

Derek Curtis Replied

Yesterday at 5:53 PM

Employee Post

The release is now live: Build 9543 (February 16, 2026).

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

John C. Reid Replied

Yesterday at 5:53 PM

There it is! Please disregard my last message.

John C. Reid / Technology Director John@prime42.net / (530) 691-0042 1300 West Street, Suite 206, Redding, CA 96001

Derek Curtis Replied

Yesterday at 5:56 PM

Employee Post

No worries, John.

Derek Curtis CCO SmarterTools Inc. www.smartertools.com

John C. Reid Replied

Yesterday at 6:18 PM

FYI - Just to confirm, I tested and it appears Build 9543 fixed the issue for me.

John C. Reid / Technology Director John@prime42.net / (530) 691-0042 1300 West Street, Suite 206, Redding, CA 96001

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Charalampos Michael Replied

Yesterday at 6:42 PM

THANK YOU! I restored IDS rules to default too! 9543 fixed the problem!

Mathieu Peloquin Replied

Yesterday at 7:22 PM

Same here, had issues, first was thinking it was due to a special build of eM Client I had received to fix an issue but glad to see 9543 fixed the problem for me too. Was pulling hair (on a bald head)! LOL!

d

digital.iway Replied

Yesterday at 10:19 PM

I upgraded to 9543 and IMAP is working with good sync from outlook, webmail and eas, but one issue to report with attachments encoding on an EAS device in sent items only. I did report this on my ticket.

Sequence/Testing:
I sent a pdf attachment from outlook using three different encoding types RICH TEXT, PLAIN TEXT, HTML. If I view the message in sent items on an IPHONE using EAS and the message is in RICH TEXT from outlook, the pdf will not display and it will show winmail.dat as the attached file not the actual pdf. PLAIN TEXT and HTML format show the attached pdf fine in sent items.

If I send the pdf attachment with RICH TEXT or HTML or PLAIN TEXT from outlook to my own inbox (all three) will render the pdf fine.

This seems to be an encoding issue with only the sent items and (RICH TEXT) on an EAS device.

My Outlook Version:
Microsoft® Outlook® for Microsoft 365 MSO (Version 2602 Build 16.0.19725.20058) 64-bi

Anyone else seeing this same issue?

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George Replied

Today at 12:45 AM

After updating to build 9543, IMAP folders can be synchronized again. Unfortunately, however, an error occurs during synchronization in MS Outlook. Items that could not be synchronized due to an IMAP error in build 9540 still cannot be synchronized. I see errors such as the following in the server log:

response: q5x5 BAD APPEND invalid arguments

response: (\Seen) BAD Command does not exist or is not implemented

command: Sent (\\Seen) "17-Feb-2026 03:15:00 +0100" {15288}

response: Sent BAD Command does not exist or is not implemented

Closing transmission channel: too many bad commands

And MS Outlook still shows synchronization errors in the sent folder. If I move them manually elsewhere, it works and they synchronize. But I can't do that for everyone.

I tried to delete the contents of the Sent folder. It worked, but then these errors appeared in the log. No one has lost anything yet, but it still doesn't work the same as in build 9526.

Failed to fetch data item 75 from GRP file for xxx @ xxx .cz in Sent.

Failed to fetch data item 76 from GRP file for xxx @ xxx .cz in Sent.

Has anyone else had the same experience? Or a solution other than manual intervention for each user?

I still have an open ticket, so we'll see.

J

J. LaDow Replied

Today at 1:09 AM

Many times, after problems with a build, if a user is continuing to have issues in Outlook, resetting the user's profile in Outlook resolves it. Not sure if this applies, but it sounds like there is some stale data on the client side from when the server was having exceptions with the bad build - so the shoe fits, so to speak...

MailEnable survivor / convert --

Sébastien Riccio Replied

Today at 1:58 AM

Those BAD APPEND arguments stink. It's like of the server doesn't understand the command sent by the client.

But is it really the client sending bad commands and or arguments, or the server that can't handle them...

Sébastien Riccio System & Network Admin https://swisscenter.com

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terry fairbrother Replied

Today at 2:08 AM

I hope the limit is a temporary fix, I have clients that send large emails regularly, we have a cap of 100Mb. 16Mb is nothing these days, Providers such as Gmail are 25Mb

If the cap is permanent, this feels like those that use imap on the free version are being targeted to force a purchase to use MAPI, but your minimum user count is way too high for smaller companies.

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J. LaDow Replied

Today at 2:21 AM

According to Derek, the cap will be tied to the setting on the domain for the maximum allowed message / attachment sizes (as of build 9543) --

MailEnable survivor / convert --

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fatih.gulsuyu Replied

Today at 2:53 AM

Based on the testing performed by our users, the IMAP synchronization problems appear to be resolved with the newer build. However, for some users there are still items remaining from the problematic version that cannot be synchronized, exactly as George described. As LaDow mentioned, when the Outlook profile is removed and the account is configured again from scratch, the synchronization issues are resolved.

For environments with only a few users, we can still recommend this approach as a workaround. Unfortunately, for customers with a large number of users this is not always practical, and we are continuing to experience operational difficulties in those cases.

Additionally, as many others have pointed out, we would like to emphasize that having a reliable downgrade option remains extremely important. Being able to temporarily return to previously stable builds that we know worked without issues is critical for maintaining service continuity in production environments.

Sébastien Riccio Replied

Today at 3:06 AM

Size limit bound to attachment size ? But what if the mail is 200mb of text (no attachements) or the text is considered as attachment :)

Sébastien Riccio System & Network Admin https://swisscenter.com

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J. LaDow Replied

Today at 3:24 AM

So in the domain settings (Options) - there are two size limits defined - Message and Attachment. The assumption based on what's been announced is the limits would be applied respectively. I believe this whole issue popped up due to changes in IMAP code that either started enforcing these limits or changed how it was done from previous builds.

MailEnable survivor / convert --

Sébastien Riccio Replied

Today at 4:31 AM

It's always a pleasure to learn changes from other users/admin instead of clear explanations in changelogs.

At least it was possible to disassemble exe and dll's to read the code and understand what is going on.

I guess no more now that code is obfuscated.

Sébastien Riccio System & Network Admin https://swisscenter.com

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Nathan Replied

Today at 5:34 AM

I can understand obfuscation being attractive but it also feels like security through obscurity. It would be nice to know in future that SM undergoes regular third-party review.

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