This is my scenario

We use exchange to send internal emails, share calendar, ect, we use and
outside service to receive external emails.

Hi guys something weird is happening here with one user

when one user cpalermo CC people within the office (ex.cnicholes) and does
"sent to" someone outside the office and when the person from the outside
replies he receives the following message:

Subject: Delivery Status Notification (Failure)

The following message to <cnicholes@mydomain.local> was

undeliverable.

The reason for the problem:

5.1.2 - Bad destination host 'DNS Hard Error looking up

mydomain.local (MX): NXDomain'

When I go to cnicholes account in AD his default emial address is
cnicholes@mydomaim.com which is correct and this is how it should be. His
secondary is cnicholes@mydomain.local

I would apreciate if some one can tell me or help me look for a solution for
this one. This is only happening with this one user.

Thanks to everyone in advance.

Denise