smtp.uzsci.net has no CNAME records.
Question and response
Question
dig smtp.uzsci.net. NS
Answer
The response has no answer records.
Authority
uzsci.net. 3125 SOA ns01.uzsci.net. root.ns01.uzsci.net. 2026021201 3600 600 1209600 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0