Apex domains cannot have CNAME records.
Question and response
Question
dig st.uz. NS
Answer
st.uz. 5 NS ns1.st.uz.
st.uz. 5 NS ns2.st.uz.
Authority
The response has no authority records.
Additional
ns2.st.uz. 5 A 217.29.116.2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0