Comment 8 for bug 388723

actually, I think the issue is that 'bzr-email' always tries 'STARTTLS' regardless if the server says it is available.

The best fix would be to change bzr-email to use bzrlib.smtp_connection instead of its own. There we have:

if self._connection.has_extn("starttls"):
    code, resp = self._connection.starttls()
    if not (200 <= code <= 299):
        raise SMTPError("server refused STARTTLS: %d %s" % (code, resp))
    # Say EHLO again, to check for newly revealed features
    code, resp = self._connection.ehlo()
    if not (200 <= code <= 299):
        raise SMTPError("server refused EHLO: %d %s" % (code, resp))

Or possibly fix bzr-email itself with that sort of fix.