We recently upgraded from SBS2003 to 2008 R2 and Exchange 2010. Most outgoing mail works just fine, but a few domains cause this error.
From: Microsoft Outlook
Sent: Wednesday, October 20, 2010 2:22 PM
To: Cindy Shirley
Subject: Delivery delayed:RE: Test email
Delivery is delayed to these recipients or groups:
Subject: RE: Test email
This message hasn't been delivered yet. Delivery will continue to be attempted.
The server will keep trying to deliver this message for the next 1 days, 19 hours and 53 minutes. You'll be notified if the message can't be delivered by that time.
I can telnet to the recipients server and queue a message up, so I cant figure out the problem.