smtpmail/starttls starts connection but never sends

[Joost Kremers <joostkremers@yahoo.com>]

Hi all,

I'm running Emacs 24.2 on OS X Lion (more precisely, I'm using the
emacs-mac-port from <https://github.com/railwaycat/emacs-mac-port>) and
using it for email with mu4e. The other day, I ran into a problem with
sending mail, in that I can't anymore...

The emacs-mac-port is compiled without tls, so it uses the external
gnutls program for establishing tls connections, which worked fine,
until Homebrew upgraded gnutls. The problem is that gnutls-cli stopped
accepting certificates that cannot be verified. As a result, the
connection would be dropped and Emacs would tell me that no smtpmail
process was running. (Note: mu4e uses message-mode for composing and
smtpmail for sending email, so this issue shouldn't be mu4e-specific).

After some googling, I found that one way to get around this *should* be
to establish a connection manually once with the --tofu option, accept
the certificate when asked to, and then add the --tofu option to
starttls-extra-arguments, as explained in a post to gnu.emacs.gnus:
<mailman.471.1333501703.20052.info-gnus-english@gnu.org>.

In my case, this doesn't entirely work, however. Although the connection
appears to be established, nothing is actually sent. I get the following
message in the minibuffer:

Opening STARTTLS connection to `mailer.gwdg.de:25'...done

and that's where it stays. Emacs is locked, the message buffer remains
open and active and nothing happens. I have to hit C-g to get control
back.

Anyone know what might be going on, or how I could debug this further?

TIA

-- 
Joost Kremers                                      joostkremers@yahoo.com
Selbst in die Unterwelt dringt durch Spalten Licht
EN:SiS(9)