mx1.spaceweb.ru has no CNAME records.
Question and response
Question
dig mx1.spaceweb.ru. NS
Answer
The response has no answer records.
Authority
spaceweb.ru. 300 SOA ns1.sweb.ru. postmaster.sweb.ru. 2022090962 7200 3600 14400 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0