We got the majority of our email flowing again yesterday after same strangeness had happened.

However we have a number of outbound queues that just won't budge.

E.g. the queue for emails sent to a yahoo.co.uk address.

Messages in this queue that were stuck yesterday are still stuck. Some new messages arrive in to the queue and get stuck alongside them. Other messages arrive in the same queue, get stuck, but then go if i restart the SMTP service.

Emails to most addresses seem to be moving fine, it is mainly hotmail, yahoo, and a few others that seem to be causing problems.

This is the particularly strange bit.... I've tried deleting the stuck messages and they vanish from the queue. If I then restart SMTP service, they reappear!? - I thought they were supposed be deleted permanently if I deleted them from the queue.