A client of our's email isn't working via outlook. I thought perhaps the pst was bad, but it is failing on all computers with outlook. I tested on their system to the web version and it signed in fine. I went back and deleted the mail account on their computer and set it up as active sync and it works fine from outlook. However, if I try to add their email as an IMAP as it is created on the mail server, it fails.
I adjusted the IP from 143 to also try 993. Also attempted with the firewall disabled. It was working fine for a while up to today. The error is uploaded.