Apex domains cannot have CNAME records.
Question and response
Question
dig itsystems.ua. NS
Answer
itsystems.ua. 5 NS ns2.itsinternet.net.
itsystems.ua. 5 NS ns.itsinternet.net.
Authority
The response has no authority records.
Additional
ns.itsinternet.net. 5 A 213.133.164.35
ns2.itsinternet.net. 5 A 185.176.120.8
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0