This is a very bizare situation and I do not know exactly what triggered it. We have Exchange 2003 SP1 in a Windows 2003 AD environment. Our desktop clients are all Outlook 2003.
For some reason, when users try to send to mail enabled groups from Outlook 2003, they don't send. The odd thing about this is that all of the mail in the mail store is set to archive to a specific mailbox. The mail is being sent to the archive mail address but not to the recipiants in the mail enabled group.
However if we send mail through Outlook Web Access, we're able to send to mail enabled groups without any problem.
I'm not sure why this has started happening all of the sudden, but i have tried unsuccessfully to troubleshoot it. I have used Message Tracking but there are no errors other than the fact that when the email comes from outlook it only sends the mail to the archive address but when it comes from OWA it sends it to the email group, splits the message and delivers it locally to all of the members of the group.
I don't understand what the problem could be or what could be causing it.