Addendum:
Shortly afterwards, I fully receive a bounce probe message, with the message sent to -owner as attachment. So, the message reaches me, Mailman somehow bounces it anyways...
2010/12/14 Florian Effenberger <floeff@gmail.com>:
Hello,
on all my mailing lists, I have the problem that mails to the -owner alias seem to bounce. The sender doesn't receive a bounce, but the list owners don't receive the e-mail -- instead, failures are logged in mailman's bounce log. The owners are the same as the subscribers (it's an internal list), and mails to the list reach these destinations itself, so it can't be a general problem. The receipients are within and outside of our domain.
I'm a bit clueless and can't find much in the logs. Any idea where to start searching?
Thanks, Florian