Apex domains cannot have CNAME records.
Question and response
Question
dig od.ua. NS
Answer
od.ua. 5 NS ns.od.ua.
od.ua. 5 NS nix.ns.ua.
od.ua. 5 NS ho1.ns.od.ua.
od.ua. 5 NS sx.ns.ua.
Authority
The response has no authority records.
Additional
ns.od.ua. 5 A 167.99.46.217
ho1.ns.od.ua. 5 A 195.47.253.7
ho1.ns.od.ua. 5 AAAA 2001:67c:258:0:0:0:0:7
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0