Apex domains cannot have CNAME records.
Question and response
Question
dig nautic-surfogski.dk. NS
Answer
nautic-surfogski.dk. 5 NS ns01.one.com.
nautic-surfogski.dk. 5 NS ns02.one.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0