Hey guys. So I currently have Exchange 2010 and Exchange 2003 in a co-existence environment. I’ve moved several users from Exchange 2003 to Exchange 2010.
Now, the problem is some of the users who are owners of their own mailboxes are able to send as themselves while some are not able to do so. Example: UserA tries to send out an email but after sending it out, she receives an NDR saying that UserA does not have permission to send as UserA. I’ve checked in the AD and EMC that she has “NTSelf” and the permission for Send As for NTSelf is allow.
My current workaround this weird issue is to add the user under “Send On behalf” in the Delivery Options. I shouldn’t have to do this if the user trying to send the email is the owner of the mailbox.