Apex domains cannot have CNAME records.
Question and response
Question
dig so.ua. NS
Answer
so.ua. 5 NS ns10.uadns.com.
so.ua. 5 NS ns11.uadns.com.
so.ua. 5 NS ns12.uadns.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0