1. Outlook.exe/cleanrules (make a copy of the rule)
2. Accepting or denying a meeting request causes a "5.1.1" non-delivery report in Exchange Server
3. Make sure you are up to date on your Exchange patches; it will not correct your current issue; but prevent further ones I believe.
Members of your organization may receive a non-delivery report if your delegate’s mailbox object is removed from Active Directory before you can remove the delegate in Outlook 2003
i have a user that when requesting a meeting and the other side responds the other side get a ndr about a user that no longer is avalible in the company
this only happens on meeting request from this user i can not find were this problem maybe thanks