We have a few users that have a sporadic problem sending messages. All users are using Outlook 2003 on XP SP3. Our server is running Exchange 2003. All users and servers are in the same AD domain.
The issue is sporadic - sometimes they'll get an NDR when they try to send an e-mail to someone, and sometimes the message goes through without any trouble. This happens with both external recipients and other recipients on our Exchange server.
Here is the NDR they receive:
From: System Administrator
Sent: Wednesday, April 28, 2010 3:43 PM
Subject: Undeliverable: Fw: subject
Your message did not reach some or all of the intended recipients.
Subject: RE: Fw: subject
Sent: 4/28/2010 3:43 PM
The following recipient(s) could not be reached:
Joe User on 4/28/2010 3:43 PM
None of your e-mail accounts could send to this recipient.
None of the users have any accounts set up in Outlook other than their Exchange account. All of the users are connecting to Exchange via the native Outlook MAPI, no POP3 or IMAP is being used.