Delegate issue -

When someone sends a meeting request to a user, they receive an NDR from another user. The unknown user was at one time a delegate for the user the meeting request was sent to and has had their user account deleted. This happens when the delegate’s user account is removed from Active Directory before being removed from the delegates list.

To resolve the issue, please follow the steps below:
1. Take note of any delegates you currently have, and remove them.
2. Take note of any rules you currently have, please note that the rules will be removed and you will need to recreate them when you are done.
3. Go to Start > Run and type in “outlook.exe /cleanrules” without the quotes and click OK.
4. This will open Outlook and remove all rules, including the invisible rule that is forwarding the message to the old delegate.
5. Go back in and re-assign delegates as needed.
6. Go back in and recreate rules as needed.