[Dovecot] Not an IMAP4 Server?

[Magnus Holmgren]

John Gray wrote:
> I've been testing alpha4, and every once in a while my client
> (Thunderbird 1.5 RC1) tells me the dovecot isn't a valid IMAP4 server. 
> This is usually (maybe always) when I first bring up  the client up.  If
> I just ask the client to get the mail again, it does so happily (without
> any errors).

IIRC, I've encountered that or a similar message (in TB 1.0.6) when the
server uses SSL/TLS and the certificate is expired or not trusted,
causing Thunderbird to pop up a warning, which gets ignored (since the
user is doing something else while Thunderbird starts up) until the
connection times out. When the user clicks OK, Thunderbird tries to
proceed but the connection is reset, triggering the totally confusing
error message.

I don't know if it's it - you should have noticed any such message box,
but maybe you didn't think about it. It could also be something similar,
with an unexpectedly broken connection in common.

-- 
Magnus Holmgren