mail.hitrost.com has no CNAME records.
Question and response
Question
dig mail.hitrost.com. NS
Answer
The response has no answer records.
Authority
hitrost.com. 142 SOA dns1.hitrost.net. hostmaster.hitrost.com. 2024092602 7200 3600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0