Apex domains cannot have CNAME records.
Question and response
Question
dig sortremoulade.dk. NS
Answer
sortremoulade.dk. 4 NS ns4.powerhosting.dk.
sortremoulade.dk. 4 NS ns1.powerhosting.dk.
sortremoulade.dk. 4 NS ns5.powerhosting.dk.
sortremoulade.dk. 4 NS ns2.powerhosting.dk.
sortremoulade.dk. 4 NS ns3.powerhosting.dk.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0