I have a client who is having issues with sending messages out to contacts whose emails belong to MSN.com or Hotmail.com. This is the only person having issues in the company. She can message back and forth just fine to anyone else. I have attempted to add external DNS servers including the MSN.com external address. Messages are just sitting in the queue.
Here is an example email she is receiving from the server:
Your message did not reach some or all of the intended recipients.
Subject: RE: Note
Sent: 8/28/2012 11:28 AM
The following recipient(s) could not be reached:
Carol on 8/30/2012 12:00 PM
Could not deliver the message in the time limit specified. Please retry or contact your administrator.