Apex domains cannot have CNAME records.
Question and response
Question
dig ipnordic.dk. NS
Answer
ipnordic.dk. 5 NS ns0169.secondary.cloudflare.com.
ipnordic.dk. 5 NS ns61.ipnordic.dk.
ipnordic.dk. 5 NS ns81.ipnordic.dk.
ipnordic.dk. 5 NS ns0011.secondary.cloudflare.com.
Authority
The response has no authority records.
Additional
ns61.ipnordic.dk. 5 A 185.72.210.10
ns81.ipnordic.dk. 5 A 185.72.208.10
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0