hmmm ok so lets see.
your domain is: qwerty.com
you have a user name: X
you have a pop3 service for your exchange: pop.qwerty.com
Problem: when you send an email From:
x@qwerty.com To:
x@qwerty.com it doesn't send because it considers it a loop.
do you receive an NDR?
In my opinion there is no loop here, be cause you are just receiving email at 2 different places from same mailbox.