I have three different Virtualmin GPL servers sporting the same issue with dovecot. No users seem to be able to authenticate, or access mail. This seemed to start right about the time that 3.88 was released, but that could be coincidence.
One server still states that it’s on 3.87 (with no available updates), the others are on 3.88. One was upgraded from 3.87, the other was actually a fresh install yesterday.
All there give this error in the maillog:
Sep 24 06:27:37 twist dovecot: auth: Fatal: Unknown authentication mechanism ‘HASH(0x3912708)’
Sep 24 06:27:37 twist dovecot: master: Error: service(auth): command startup failed, throttling
I’ve also seen:
Sep 24 06:33:05 fun dovecot: pop3-login: Disconnected: Inactivity (no auth attempts): rip=::1, lip=::1, mpid=0, secured
Sep 24 06:37:02 taco dovecot: pop3-login: Error: Timeout waiting for handshake from auth server. my pid=22674, input bytes=0
Anyone have any similar issues, and/or a direction to point me in for resolution? Dovecot is really not my area.