Apex domains cannot have CNAME records.
Question and response
Question
dig columbus.te.ua. NS
Answer
columbus.te.ua. 5 NS ns2.columbus.te.ua.
columbus.te.ua. 5 NS ns1.columbus.te.ua.
columbus.te.ua. 5 NS ns8.maxnet.ua.
columbus.te.ua. 5 NS ns5.maxnet.ua.
Authority
The response has no authority records.
Additional
ns1.columbus.te.ua. 5 A 185.53.79.2
ns2.columbus.te.ua. 5 A 185.53.79.3
ns5.maxnet.ua. 5 A 178.165.81.4
ns8.maxnet.ua. 5 A 31.202.15.2
ns5.maxnet.ua. 5 AAAA 2a00:1210:0:2:0:0:0:2
ns8.maxnet.ua. 5 AAAA 2a00:1210:fffe:0:0:0:0:2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0