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