mx.plingest.com has no CNAME records.
Question and response
Question
dig mx.plingest.com. NS
Answer
The response has no answer records.
Authority
plingest.com. 558 SOA ns59.domaincontrol.com. dns.jomax.net. 2025072403 28800 7200 604800 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0