Apex domains cannot have CNAME records.
Question and response
Question
dig oxem22.net. NS
Answer
oxem22.net. 5 NS nssec.online.net.
oxem22.net. 5 NS ns.oxem22.net.
Authority
The response has no authority records.
Additional
ns.oxem22.net. 5 A 212.129.53.104
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0