We just unmerged with a company that we merged into our AD and exchange. Now that they have left, we cannot email them (have not deleted their mailboxes - but disabled their accounts) from internally. I have deleted cached information on our outlooks and manually retyped their address.
No error because I believe our server is still accepting the emails.
Removed them from HUB transport rules - accepted domains - address policies.. no luck
We have Exchange 2010 on 2008 server.... any help appreciated.