Apex domains cannot have CNAME records.
Question and response
Question
dig omnitel.biz. NS
Answer
omnitel.biz. 5 NS ns2.omnitel.biz.
omnitel.biz. 5 NS ns1.omnitel.biz.
Authority
The response has no authority records.
Additional
ns1.omnitel.biz. 5 A 216.51.135.137
ns2.omnitel.biz. 5 A 216.51.135.138
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0