Messages randomly not accessible to random users

Parrish Reinoehl - 10:29pm, Feb 28 2020

I'm having a very strange problem that we haven't been able to resolve.  I have been working with Alt-N support but we can't nail down the cause. 

So, hopefully, someone here might have some ideas. 

We are running Mdaemon 19.5.4 on a Server 2012 box.  It is a 32bit install.   

We are having an issue where a random user is unable to access their messages either via IMAP or Webmail.  The user that is affected appears to be completely random. The frequency of this happening seems to be a few times per week.   

What they will notice is that Outlook will stop receiving new messages.  They can send messages without any issue. If they log in via Webmail it will allow them to log in but it will not display any messages (although it does show the total number of messages present in the account). When I look at the Mdaemon sessions I can see they are logged in so this is not an issue with the user or IP being blacklisted (and I have verified their IP address is not showing up in any blacklists).   

I have to stop and then restart the Mdaemon service.  As soon as I do that, and immediately after Mdaemon starts back up, all of their emails will load in to Outlook (Outlook is configured using IMAP). Webmail will also now display all of their messages. 

I have verified that the entire Mdaemon directory and subdirectories are excluded from the antivirus (which is Avast CloudCare).  The user folders are in their standard location within the Mdaemon directory and it is located on the C: drive of the server (so not on a NAS or anything like that).   

I have sent various log files to Alt-N support but nothing is showing up as being a problem.  

My users are growing extremely impatient with this.  Does anyone have any ideas of what else I should be looking at?   

This customer was previously on an old version, 16.5, and was experiencing this issue maybe once per month or so.  I renewed their Mdaemon support contract so we could upgrade them to 19.5.4 in the hopes it would resolve the trouble. But, in actuality, it's made the trouble much more prominent as it now happens a few times (or more) per week.