mx03.unifiedpost.com has no CNAME records.
Question and response
Question
dig mx03.unifiedpost.com. NS
Answer
The response has no answer records.
Authority
unifiedpost.com. 3127 SOA public-ns1.unifiedpost.com. hostmaster.unifiedpost.com. 2025121102 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0