F12: Sendmail/Thunderbird send email problem?

[Daniel B. Thurman]

For some reason, I am unable to get sendmail to send
email message using TLS/SSL using Thunderbird.  What is
odd, is that I am constantly asked to provide the password,
and I did that, over and over only to be forced to cancel the
send request.  I am not having any issues with F9 & F11 - it
works, just not with F12.

The Mail log shows:

Feb 20 13:06:16 <server> sendmail[7872]: STARTTLS=server, relay=<server>
[10.1.0.1], version=TLSv1/SSLv3, verify=NO,
cipher=DHE-RSA-CAMELLIA256-SHA, bits=256/256

Feb 20 13:06:23 <server> sendmail[7872]: o1KL6GOL007872: <server>
[10.1.0.1] did not issue MAIL/EXPN/VRFY/ETRN during connection to MTA

What does the 2nd line mean?  Cancelled send request?

Using the 'mail' command line, it seems to work.

Perhaps this is a Thunderbird configuration issue?

Perplexed,
Dan