Mutt question

[Michael Ward Cole]

I have a problem sending email to one domain.  
My email is sent through home.com and every time that I send mail to another 
person with the same domain name I get a message undeliverable message saying 
that it can't find the local-part of the domain.  Now, does this mean that it 
is looking locally for the host/user and not sending the email to the server?  
If so, where do I go to make the necessary changes?
Thanks,
Michael