mx.terabit.net.ua has no CNAME records.
Question and response
Question
dig mx.terabit.net.ua. NS
Answer
The response has no answer records.
Authority
terabit.net.ua. 1246 SOA ns.terabit.net.ua. noc.terabit.net.ua. 2024112700 14400 7200 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0