mx.redham.ru has no CNAME records.
Question and response
Question
dig mx.redham.ru. NS
Answer
The response has no answer records.
Authority
redham.ru. 3188 SOA ns1.redham.ru. support.redham.ru. 2022071664 900 600 86400 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0