Apex domains cannot have CNAME records.
Question and response
Question
dig powerhosting.dk. NS
Answer
powerhosting.dk. 3 NS kay.ns.cloudflare.com.
powerhosting.dk. 3 NS alex.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
kay.ns.cloudflare.com. 1 A 108.162.192.125
kay.ns.cloudflare.com. 1 A 172.64.32.125
kay.ns.cloudflare.com. 1 A 173.245.58.125
alex.ns.cloudflare.com. 1 A 108.162.193.100
alex.ns.cloudflare.com. 1 A 172.64.33.100
alex.ns.cloudflare.com. 1 A 173.245.59.100
kay.ns.cloudflare.com. 1 AAAA 2606:4700:50:0:0:0:adf5:3a7d
kay.ns.cloudflare.com. 1 AAAA 2803:f800:50:0:0:0:6ca2:c07d
kay.ns.cloudflare.com. 1 AAAA 2a06:98c1:50:0:0:0:ac40:207d
alex.ns.cloudflare.com. 1 AAAA 2606:4700:58:0:0:0:adf5:3b64
alex.ns.cloudflare.com. 1 AAAA 2803:f800:50:0:0:0:6ca2:c164
alex.ns.cloudflare.com. 1 AAAA 2a06:98c1:50:0:0:0:ac40:2164
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0