mail.TASHIRTELECOM.RU has no CNAME records.
Question and response
Question
dig mail.TASHIRTELECOM.RU. NS
Answer
The response has no answer records.
Authority
TASHIRTELECOM.RU. 6715 SOA ns1.ttcom.RU. support.TASHIRTELECOM.RU. 2025081104 28800 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0