Apex domains cannot have CNAME records.
Question and response
Question
dig domtele.com. NS
Answer
domtele.com. 5 NS ns2.datagroup.com.ua.
domtele.com. 5 NS ns.datagroup.com.ua.
Authority
The response has no authority records.
Additional
ns.datagroup.com.ua. 5 A 80.91.160.2
ns2.datagroup.com.ua. 5 A 80.91.160.3
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0