Hangs when sending mail via SMTP

[Tassilo Horn <tassilo@member.fsf.org>]

Hi all,

since 2 or three days (always using the current git master), I have
frequent hangs when sending mail via SMTP.  In *Messages* I get the
usual output:

--8<---------------cut here---------------start------------->8---
235 2.7.0 Authentication successful
250 2.1.0 Ok
250 2.1.5 Ok [4 times]
354 End data with <CR><LF>.<CR><LF>
Sending email 
Sending email done
250 2.0.0 Ok: queued as 28C71D244A
221 2.0.0 Bye
Mark set
Sending...done
--8<---------------cut here---------------end--------------->8---

The hang occurs while "Mark set" is shown in the echo area.  It usually
takes about 20-30 seconds before "Sending...done" appears and the mail
buffer is closed.

What's a bit strange: when I hit C-g during the hang (possibly
repeatedly), I'll get the "Sending...done" immediately without noticing
any bad effect.  The sent mail is also copied to the group I wrote from
as specified by gcc-self setting.

I can also invoke "killall emacs" from the command line which won't kill
emacs but interrupt the hang just as C-g.

Hm, it might not be a Gnus problem, as the latest commits don't look
overly related.  In the same period, I updated my emacs bzr checkout
(TLS issue maybe?) and our university's mail server machine crashed and
was replaced...

Anyway, does anyone have similar issues?

Bye,
Tassilo