We have begun moving mailboxes from Exchange 2003 to Exchange 2007 and are getting several NDR messages a day from both Internal and External sources to accounts that have not yet been moved.
I have checked a couple of these accounts, and they has no limitations on who can send email to them.
The issue here I believe is the hub transport server, as it had been inactive for the most part before the move. However the accounts on the Exchange Server 2007 do not seem to have this issue.
The size the mail stores is over 150GB so it will take more than a fews to get past this. Especially since they will only give us 6 hours/day to move the boxes.
Any ideas on what we are missing here?
Below is what we are seeing: