mx5.beget.ru has no CNAME records.
Question and response
Question
dig mx5.beget.ru. NS
Answer
The response has no answer records.
Authority
beget.ru. 300 SOA ns1.beget.com. hostmaster.beget.com. 1771582061 300 600 86400 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0