mx1.NETONE.RU has no CNAME records.
Question and response
Question
dig mx1.NETONE.RU. NS
Answer
The response has no answer records.
Authority
netone.ru. 1542 SOA ns1.netone.ru. tech.netone.ru. 2020111867 10800 3600 3600000 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0