IMAP failure

ClearOS release 7.9.1 (Final) running, imap server is running, according to the GUI. However, the last connection from Apple Mail was yesterday afternoon around 5 p.m. and I cannot connect to IMAP this afternoon at all. From the event log, I see the Cyrus user logging in and out, so it appears all is running on the ClearOS server, yet, none of my clients will connect. I tried a password change, no luck. Tried setting up a POP account and get the "can't verify user or password" error. I've done everything my Linux challenged abilities knows to do other than uninstalling and reinstalling the IMAP server. Also checked the firewall, and ports 143 and 993 are both open. In Apple's connection doctor window, I can see the mail client attempting to connect via both ports with no success. Very frustrating, any suggestions appreciated.