[Mailman-Users] Hotmail problems

[David]

Dear gurus,

My server and my Hotmail subscribers are in a loop right now. They are
getting one specific mail posted to a list of mine over and over again.

How can I stop this? I'm running Mailman 2.1.1 and Postfix 2.0.4.
I have restarted the qrunners and flushed the Postfix mail queue.

Please give me some advice how to track down this kind of problem :)

 Blue Skies,
 /David