What version of outlook?

Hello! We'd be happy to take a look at this for you as well. First; I have a couple of questions to help us get some more details: 

- Have you identified any common variables across the users who can't use Reply All functionality? 

- Are all of the affected users on the same version of Outlook and using the MAPI protocol? 

- Are there specific threads that this happens on more often than not?

- What version of SmarterMail is in use here?

Different outlook version 2019/2021/2024, the acoount afflicted MAPI.

Different customer, different domain, different firewall, different email, the only common is Smartermail server

Latest version of SM

Are you or one of these users able to replicate on demand, or is this more sporadic? I ask because a Fiddler trace may be best in getting an idea of what it is doing since the issue looks to be happening inside of Outlook somewhere. Can I have you download and install Fiddler Web Debugger (Classic), configure to decrypt HTTPS traffic, then run it while reproducing the issue a couple of times? At that point you can export it as an SAZ file and send that our way in a ticket for review. Thank you in advance. 

This is the email fo my customer:

"non è visibile il mittente e anche quando faccio un inoltra, nella mail che inoltro non si vede il mittente, ti allego screenshot.

È un’impostazione assolutamente da sistemare.

La questione del “rispondi a tutti” infine è per noi molto importante poiché mandiamo mail anche a 10 destinatari e, dato che sono più settimane che riscontriamo questo errore, urge una rapida soluzione"

news for the new release of the software that solve the problem?

I have installed windows 11 and office english version in a laptop i have the same problem, reply all not working and sender missing, i don't understand how you are unable to replicate the problem.

We did some tests on the laptop mentioned earlier.
Info:
Fukitsu Lifebook A series
i5-6200 4GB RAM Win11Pro

With this configuration reply all is not working. We tried changing the ram to 16GB and the problem was the same.
We tried formatting the laptop with the same OS and it seemed to work. After that I tried putting the 4GB ram back and 16GB and sometimes the problem comes back and sometimes it doesn't(I couldn't figure out why).
This problem is not encountered if I use an email address that is not from Smartermail.

There was always the sender missing every configuration I did.

Thanks for your follow up. We will still need some additional details to help so I'll recap my questions: 

I looked to see if you had opened tickets on this issue, and you have, but you have not provided us with any Fiddler traces to see if there are any errors.  It would be impossible to help you without this information and/or a message that is causing the issue.  We are here and we are waiting to help.  

We need a fiddler trace from a clients machine / outlook having the issue to resolve your problem.  Customers know all to well how avaliable we are and how good our support is and all your tickets are just belittling us and my team.   Anymore of that, and we will no longer support you. Your choice!

Here you are. (EDIT: Trace sent in a ticket to us.)

I have the same (or similar) problem on my personal computer. Running MS Office 365 with the latest updates installed. I can Reply but when I attempt to Reply All, I get an "Out of memory or system resources" error message. Do you want me to open a ticket?

If you check the sent items, can you see the sender name in the correct filed or is empty?

@Skillworks -- we got the trace in your ticket. Thanks! I removed the download from your post as it's probably not something you want public. 

@Brian -- I started a ticket with you on this. It appears this is a relatively common issue with Outlook, but we'll dig in and see if it's SmarterMail that's causing the issue.

Thanks Derek. For clarification, I am experiencing this on my personal computer, my computer at work does not have this issue. My work computer has four email accounts in Outlook and my personal one has roughly ten email accounts in Outlook. 

Skillworks sent in his trace and then tells us to close his ticket.

These are the oddities we deal with trying to help customers. Some people just want to complain, belittle, or be difficult and then come to the community and complain that we don't help them. And all we want to do is fix issues for people, not manage personalities.  

But, we don't let those who do this distract from those who are kind and considerate and just looking for help.  

Yes, it seems to be an Outlook problem.  See below for my results when searching for "Outlook error on Reply All"

Based on that result:

- Are the multiple complaints about "reply all" related to the same distribution list(s)?  Maybe the list is corrupted

- Any chance that the distribution list includes an entry taken from a user's corrupted auto-complete list?  This might be the source of the corrruption

- How many names in the reply-all list?   Maybe the request is just too hard for Outlook.

My guess is that ST will fix the problem before Microsoft can, if they have enough sample data.

When experiencing errors with the "Reply All" function in Outlook, it's often related to how Outlook identifies sender and recipient addresses, or issues with the email itself. Several troubleshooting steps can help resolve these errors, including checking recipient addresses, updating Outlook, and verifying settings.

Common causes and solutions for Reply All errors in Outlook:

1. Incorrect Sender/Recipient Identification:

Outlook might include your own address in the "Reply All" if the sending and receiving addresses don't perfectly match, especially with multiple accounts.

If you're using a different account to reply than the one the email was sent to, this can cause the issue.

Solution: Ensure you are replying from the correct account, or try removing and re-adding recipients.

Your mailbox might be full, or you may have exceeded daily sending limits or recipient limits for a single message.

Solution: Check your mailbox size and sending quotas. Consider deleting old emails or adjusting your sending habits.

Good morning

even though an email had a single recipient, if I pressed Reply, it worked, but if I pressed Reply All, it didn't. I tried several times, but reply all not working with many emails. I left Outlook open, disabled the network card, Outlook goes disconnected, and the Reply All button started working fine.

Actually i have no common value for the users afflicted.