Apex domains cannot have CNAME records.
Question and response
Question
dig oksimel18.net. NS
Answer
oksimel18.net. 5 NS ns.oksimel18.net.
oksimel18.net. 5 NS sdns2.ovh.net.
Authority
The response has no authority records.
Additional
ns.oksimel18.net. 5 A 87.98.130.133
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0