mx.astrin.uz has no CNAME records.
Question and response
Question
dig mx.astrin.uz. NS
Answer
The response has no answer records.
Authority
astrin.uz. 10800 SOA ns01.uzsci.net. root.ns01.uzsci.net. 2022102501 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0