Apex domains cannot have CNAME records.
Question and response
Question
dig dp.ua. NS
Answer
dp.ua. 5 NS s1.ns.dp.ua.
dp.ua. 5 NS s2.ns.dp.ua.
dp.ua. 5 NS s4.ns.dp.ua.
dp.ua. 5 NS ns.dp.ua.
dp.ua. 5 NS s3.ns.dp.ua.
Authority
The response has no authority records.
Additional
ns.dp.ua. 5 A 85.198.143.26
s1.ns.dp.ua. 5 A 173.249.8.145
s2.ns.dp.ua. 5 A 212.3.121.50
s3.ns.dp.ua. 5 A 51.68.213.171
s4.ns.dp.ua. 5 A 154.53.45.163
ns.dp.ua. 5 AAAA 2a01:750:1:26:0:0:0:2
s1.ns.dp.ua. 5 AAAA 2a02:c207:2014:7560:0:0:0:145
s2.ns.dp.ua. 5 AAAA 2a01:750:1:50:0:0:0:2
s3.ns.dp.ua. 5 AAAA 2001:41d0:801:2000:0:0:0:1b57
s4.ns.dp.ua. 5 AAAA 2605:a140:2081:2129:0:0:0:163
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0