mx.midphase.com has no CNAME records.
Question and response
Question
dig mx.midphase.com. NS
Answer
The response has no answer records.
Authority
midphase.com. 3073 SOA dns1.p01.nsone.net. hostmaster.nsone.net. 1731081753 43200 7200 1209600 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0