I have a user that is receiving the following error message "You do not have
permission to send to this recipient. " but only when she replies or forwards
to the person. If she types in the person's email address it works fine. It's
not just this user either. Three other people have also tested this and it's
behaved the same way. The recipient is telling us it's on our end. Any ideas?

Antivirus and Spam
Back-end Server
Multple Sites
Outlook 2003 users cannot connect through vpn"
Routing Groups?