Delivery Failure

Just installed a test Domino 6.0.1 server and configured some test user accounts to send and receive emails. I can send just fine from this Domino server, but when I attempt to reply to the test email account I get a delivery failure stating: No route found to domain KPTTest.Local from server NOTES1/KEYSTONE. Check DNS configuration.

What am I missing?

Subject: Delivery Failure

No FQDN defined in server document, probably or the test server using SMTP is not defined as an MX in your DNS