yesterday we started having problems with outgoing mail being stuck in the queue. the only message i get is "the connection was dropped due to an SMTP protocol sink". I've got 835 messages waiting to go out.
i tried everything that was recommended on this page:
but none of it seems to help the queue problem.
additionally i find this event disturbing:
Event Type: Warning
Event Source: smtpsvc
Event Category: None
Event ID: 2012
Time: 12:56:29 PM
SMTP could not connect to the DNS server 'xx.xxx.xx.xxx'. The protocol used was 'UDP'. It may be down or inaccessible.
For more information, see Help and Support Center at http://go.microsoft.com/fwlink/events.asp
0000: d5 04 00 00 ...