Hi, we have Exchange 2010 in our organization. A while back, we had a corrupted mailbox and one of our staff removed it and recreated a new one for this user. However, anyone in within our organization cannot email to this user (gets an NDR) but external incoming emails worked fine. So I created an X500 email address for this user and problem solved.
Now, we were wondering if we can remove all the x400 emails in Exchange and why do we even need the X500 email address?