mx.merlion.ru has no CNAME records.
Question and response
Question
dig mx.merlion.ru. NS
Answer
The response has no answer records.
Authority
merlion.ru. 99 SOA ns1.merlion.ru. domains.merlion.ru. 2026021603 3600 900 3600000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0