mx.hgrstrailers.com has no CNAME records.
Question and response
Question
dig mx.hgrstrailers.com. NS
Answer
The response has no answer records.
Authority
hgrstrailers.com. 494 SOA ns63.domaincontrol.com. dns.jomax.net. 2026021283 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0