Apex domains cannot have CNAME records.
Question and response
Question
dig serverprofi24.com. NS
Answer
serverprofi24.com. 5 NS ns5.nameserverservice.de.
serverprofi24.com. 5 NS ns6.nameserverservice.de.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0