Apex domains cannot have CNAME records.
Question and response
Question
dig nest.vn.ua. NS
Answer
nest.vn.ua. 5 NS ns3.nest.vinnica.ua.
nest.vn.ua. 5 NS ns4.nest.vinnica.ua.
nest.vn.ua. 5 NS ns1.nest.vinnica.ua.
nest.vn.ua. 5 NS ns2.nest.vinnica.ua.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0