Ubuntu Installation :: Evolution-to-Postfix Pop3 Authentication Fails ?

I just upgraded my Ubuntu 8.04 server to 10.04 and now I cannot receive mail on my Ubuntu 10.04 Evolution client, although I can send mail. No errors appear in auth.log or mail.log when I attempt to log in from my Evolution client, in fact mail.log shows 'pop3d-ssl: connection' from my laptop IP, followed by 'pop3d: Disconnected' when the log-in attempts fail.

I'm able to ssh into the server using the same log-on and password as before the upgrade, however I haven't changed the public or private keys in my .ssh directory. I updated the ssl keys in /etc/postfix/ssl but wasn't able to receive mail before or after the update.

The error in the client reads: 'Unable to connect to POP server mail.mydomain.com, error sending username'

I ran this test and the output appears to be related:

Is the pop3 server not running TLS? /etc/postfix/main.cf says it should, and I get no errors restarting / reloading postfix.

I am receiving messages in /home/user/Maildir, but I cannot download them.

I checked for supported authentication types in my Evolution client - 'Password' is the only one supported, as was true before. The client is not using any certificates.

The output of openssl s_client -tls1 -connect 127.0.0.1:995 shows 'certificate has expired' on the 'Verify return code' entry, not sure if that's significant.

What's different about incoming versus outgoing mail authentication?