mail.st.uz has no CNAME records.
Question and response
Question
dig mail.st.uz. NS
Answer
The response has no answer records.
Authority
st.uz. 6339 SOA ns1.st.uz. admin.st.uz. 2026022000 10800 3600 604800 86400
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0