Christopher Hatty wrote:

Our mailman server stopped sending out the following notifications:

Uncaught Bounce notifications Notification a sender gets when a post has been moderated Notifications to moderators and list admins of any kind

I have NO idea what might have precipitated this. I'm not even sure when it happened.

Can someone start me in a direction toward finding out?

My guess is VirginRunner has died and all the notices are in the virgin queue.

See http://www.python.org/cgi-bin/faqw-mm.py?req=show&file=faq04.078.htp for more on runners and queues. Also see Mailman's error and qrunner logs for possible info related to the death of VirginRunner.