I have a user that whenever he (User A) sends out a meeting request and someone accepts, they then get a non delivery report from a user (User B) that is no longer with the company.
I have checked every AD property on his (User A) account for delegates and every mailbox permission I could find. Can not find any reference to this deleted user (User B) anywhere in Exchange or AD, and I've done full dumps. Those are full AD attribute dumps with csvde and full Exchange Mailbox permission exports for all users. No reference to User B anywhere.
He is not using a local distribution group either, it happens with every meeting he sends out.
Anyone have any suggestions?