SSL alert number 42

This is a followup to my thread "Recommended Protocols?".

The error message is as follows: dovecot: imap-login: Disconnected: TLS: SSL_read() failed: SSL routines:ssl3_read_bytes:sslv3 alert bad certificate: SSL alert number 42

I have selected both SSL/TLS and STARTTLS on the Thunderbird side, with identical results.

The first question that I have is this. Is there any way to know whether that error messages comes from an attempt to read:

(a) The server SSL certificate? (b) The client SSL certificate?

Please find attached 2 log files.  I am essentially using the distribution files as they come from the box.

TIA