Apex domains cannot have CNAME records.
Question and response
Question
dig 42n.dk. NS
Answer
42n.dk. 5 NS ns0118.secondary.cloudflare.com.
42n.dk. 5 NS ns0240.secondary.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0