Apex domains cannot have CNAME records.
Question and response
Question
dig net.net. NS
Answer
net.net. 5 NS isla.ns.cloudflare.com.
net.net. 5 NS amir.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0