mail.sci.uz has no CNAME records.
Question and response
Question
dig mail.sci.uz. NS
Answer
The response has no answer records.
Authority
sci.uz. 10800 SOA ns08.uzsci.net. webmaster.uzsci.net. 1541673656 10800 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0