Re: Dovecot Problems?

[Anthony DeRobertis <anthony@derobert.net>]

Presuming you're running stable, I've got 1:2.2.13-12~deb8u1 running and
login from Android clients (K-9, Android 5 and 6) works just fine. I
would suggest using tcpdump to see how far the packets are getting.
Also, IMAP/SSL (as opposed to IMAP + STARTTLS) runs on port 993—make
sure you're not blocking that.

You could also use a telnet client on Android to test, by telnet'ing to
the IMAP port. Some trivial IMAP commands to try are "tag capability"
and "tag logout". Tag can be any tag, including "tag".