Apex domains cannot have CNAME records.
Question and response
Question
dig kpdrift.dk. NS
Answer
kpdrift.dk. 2 NS ns1.dnsservers.dk.
kpdrift.dk. 2 NS ns2.dnsservers.dk.
kpdrift.dk. 2 NS ns3.dnsservers.dk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0