When I run smtpdiag I get a couple errors. (Exchange 2003/SBS 2003)
Checking MX servers listed for firstname.lastname@example.org.
Connecting to mx.domain.net [184.108.40.206] on port 25.
Error: Expected "250". Server rejected the recipient address.
Failed to submit mail to mx.domain.net.
For the most part, email works. But there are a couple domains we can't email into. I'd like to understand and clear up that error message as a troubleshooting start....what does that mean?