Apex domains cannot have CNAME records.
Question and response
Question
dig zp.ua. NS
Answer
zp.ua. 5 NS ns.kh.ua.
zp.ua. 5 NS ns.sm.ua.
zp.ua. 5 NS nn.ns.ua.
zp.ua. 5 NS ho1.eunic.net.ua.
zp.ua. 5 NS ns.net.ua.
zp.ua. 5 NS ns.dn.ua.
Authority
The response has no authority records.
Additional
nn.ns.ua. 172753 A 194.58.197.4
ns.net.ua. 3 A 31.28.166.180
nn.ns.ua. 172753 AAAA 2a01:3f1:c001:0:0:0:0:53
ns.net.ua. 3 AAAA 2a03:6300:1:103:0:0:0:180
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0