I am using Mailenable Enterprise version 6.53 but my question could relate to any e-mail server, I suppose. We have a user that is experiencing disappearing e-mails. When he connects to his mail account on Outlook 2013, the e-mails get received but directly after receiving them, they suddenly disappear as if deleted. It disappears not only off Outlook but also off the server.
My initial thought was that he probably had POP configured and when he receives his mail it gets removed from the server. However, it turns out that he is using IMAP on all his devices when accessing his e-mails (He's only accessing his e-mail from his iPhone and PC (with Outlook) and both are configured to use IMAP.) I also thought that it might be an issue with Outlook, but after completely uninstalling Outlook and re-installing and setting up the accounts from scratch this still happens.
It happens sporadically, not consistently every day. Some days the e-mails are received fine and other days all the e-mails for the day disappear. I have checked in the actual mailbox message storage directory and the mail is completely gone there. It is not in deleted items or any other folder. It also does not show up on Webmail which indicates that the messages did, in fact, "disappear". (When logged on to Webmail one actually sees the messages disappearing from the inbox one by one and I have witnessed this.)
I thought that his login credentials might have been compromised and that someone else was doing a POP connection using his credentials, hence pulling the e-mails off the server. Therefore I suggested he change his password. This had no effect on the disappearing messages.
I am at wit's end as to what else might be causing this strange behavior. Any ideas? I can't logically think of anything else that could be causing this so I can investigate that possibility further. Any idea of what could possibly be causing this? Are there specific log files can I look at to maybe get a clue? Perhaps there is some device somewhere with a POP connection - is it possible to view which IP addresses are accessing specific accounts on MailEnable? Or perhaps it's something completely different. Any help would be appreciated, please...
EDIT: After some research it seems like many people are experiencing this on Windows 8 with Outlook 2013 (just some of many examples are here and here), yet none of them seems to have come across a workable solution. Any ideas of how to solve this?