[Dovecot] imap disconnects on my account only

[Mitch Pirtle]

Talk about personal problems!

I am using dovecot-0.99.13-4.FC2, and everything has been going fine
for months. Earlier this afternoon, Thunderbird's status pane would
say 'Sending authenticate login information...' and I would no longer
receive email.

When I checked with others, they were fine and dandy.

I tried kmail, evolution, and even tried webmail. All had connection errors.

Checking the logs I can see the following:

May 27 14:07:58 mongo imap-login: Login: mitchy [162.84.141.200]
May 27 14:07:58 mongo imap(mitchy): getgroups() failed: Invalid argument
May 27 14:07:58 mongo dovecot: child 3264 (imap) returned error 89

I can see new messages in $Maildir, so it is all about authentication,
which I am completely clueless about as it has been working for as
long as I have had this server.

What steps can I take to debug the situation?

-- Mitch