mx02.NICMAIL.RU has no CNAME records.
Question and response
Question
dig mx02.NICMAIL.RU. NS
Answer
The response has no answer records.
Authority
NICMAIL.RU. 371 SOA ns3-l2.nic.RU. info.nicservice.RU. 2019112532 14400 3600 2592000 600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0