Apex domains cannot have CNAME records.
Question and response
Question
dig primaryns.kiev.ua. NS
Answer
primaryns.kiev.ua. 5 NS primaryns.kiev.ua.
primaryns.kiev.ua. 5 NS netx2.dd.kiev.ua.
Authority
The response has no authority records.
Additional
primaryns.kiev.ua. 5 A 194.44.221.230
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0