mail.dc.uz has no CNAME records.
Question and response
Question
dig mail.dc.uz. NS
Answer
The response has no answer records.
Authority
dc.uz. 966 SOA ns1.dc.uz. admin.uzinfocom.uz. 2025102801 10800 3600 604800 10800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0