Apex domains cannot have CNAME records.
Question and response
Question
dig av-mx.com. NS
Answer
av-mx.com. 5 NS ns2.neonova.net.
av-mx.com. 5 NS ns1.neonova.net.
Authority
The response has no authority records.
Additional
ns1.neonova.net. 5 A 137.118.1.28
ns2.neonova.net. 5 A 107.155.81.154
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0