mx1.harriscomputer.com has no CNAME records.
Question and response
Question
dig mx1.harriscomputer.com. NS
Answer
The response has no answer records.
Authority
harriscomputer.com. 300 SOA dns1.easydns.com. zone.easydns.com. 1771355212 3600 600 1209600 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0