mx.xp-ml.com has no CNAME records.
Question and response
Question
dig mx.xp-ml.com. NS
Answer
The response has no answer records.
Authority
xp-ml.com. 265 SOA x.ns.joker.com. hostmaster.joker.com. 2026021164 14400 3600 604800 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0