remote server respond The smtp session has timed out
Problem reported by Manuel - November 12, 2014 at 7:22 AM
I have SmarterMail Enterprise 12.3.
Many time, when my server send email to remote server, I see response "The smtp session has timed out".
This is a log example
[2014.11.10] 14:43:34 [46094] Sending remote mail for aaaaa
[2014.11.10] 14:43:34 [46094] Initiating connection to xxxxx
[2014.11.10] 14:43:34 [46094] Connecting to xxxxx:25 (Id: 1)
[2014.11.10] 14:43:34 [46094] Binding to local IP xxxxx:0 (Id: 1)
[2014.11.10] 14:43:34 [46094] Connection to xxxx:25 from xxxxx:59907 succeeded (Id: 1)
[2014.11.10] 14:43:35 [46094] RSP: 220 bbbbb ESMTP Service ready
[2014.11.10] 14:43:35 [46094] CMD: EHLO aaaaaa
[2014.11.10] 14:43:35 [46094] RSP: 250-bbbbbbb
[2014.11.10] 14:43:35 [46094] RSP: 250-DSN
[2014.11.10] 14:43:35 [46094] RSP: 250-8BITMIME
[2014.11.10] 14:43:35 [46094] RSP: 250-PIPELINING
[2014.11.10] 14:43:35 [46094] RSP: 250-HELP
[2014.11.10] 14:43:35 [46094] RSP: 250-DELIVERBY 300
[2014.11.10] 14:43:35 [46094] RSP: 250 SIZE 31457280
[2014.11.10] 14:43:35 [46094] CMD: MAIL FROM:<aaaaa> SIZE=475445
[2014.11.10] 14:43:35 [46094] RSP: 250 MAIL FROM:<aaaaaa> OK
[2014.11.10] 14:43:35 [46094] CMD: RCPT TO:<bbbbbb>
[2014.11.10] 14:43:35 [46094] RSP: 250 RCPT TO:<bbbbbb> OK
[2014.11.10] 14:43:35 [46094] CMD: DATA
[2014.11.10] 14:43:35 [46094] RSP: 354 Start mail input; end with <CRLF>.<CRLF>
[2014.11.10] 14:44:36 [46094] The smtp session has timed out.
[2014.11.10] 14:44:36 [46094] Delay notification email written to 82246707.eml
In many cases, however, the email is delivered to the recipient.
SmarterMail server retry sending until it receives a successful response from the server of the recipient.
But, every retry, remote server response with "timeout" but email is delivered to the recipient.
What's the problem?
Is the remote server overloaded?
GRAFFITI — It's Communication
Riva del Garda (TN), I-38066 – Località Pasina 46
Milano, I-20129 - via Lamberto De Bernardi 1
Verona, I-37134 - via Legnago 126
San Francisco, US-94111 California – 275 Battery St, Suite 2600

7 Replies

Reply to Thread
Yee Cheing Seah Replied
I have the same issue, may I know do you get the solution? So is sender server have to increase the Session Timeout In setting or Receiver side did it?
John Dobbin Replied
I'm having customers calling in and complaining they can't send even small attachments and this same error is logged on Version 14.5.5871.
Scarab Replied
I've been seeing the same thing, but almost always to servers ( In the case of Microsoft's Hosted Mail Services this is how they deal with mail that is failing Anti-Spam checks. Rather than issuing a RSP 541 or other 4XX/5XX error which might give spammers an opportunity to adapt and circumvent their Anti-Spam mechanisms they just make it look like it was accepted for delivery and let the connection time out.

However, if you are getting this for several different providers though you may want to increase the Command Timeout in SETTINGS > PROTOCOL SETTINGS > SMTP OUT.
John Dobbin Replied
We have now doubled the session timeout and the issue persists.
Gabriele Maoret Replied
Same issue here! Is there a solution?
Gabriele Maoret Replied
SM 16.3.6530 has the same issue here.

Many email delivery keep to have multiple "The smtp session has timed out" errors.
This is present to various different destinations, not only to OUTLOOK.COM.
We have allready verified that canche MTU, Timeout and LAN drivers does not solve the issue.

Many customers are complaining with us.
Gabriele Maoret Replied
This issue has begun to show up again with some recipients.

Smarter mail version: 17.0.6878 

Reply to Thread