smtp.subscribe.ru has no CNAME records.
Question and response
Question
dig smtp.subscribe.ru. NS
Answer
The response has no answer records.
Authority
subscribe.ru. 3600 SOA ns.iprojects.ru. noc.iprojects.ru. 2023051226 10800 1100 864000 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0