Apex domains cannot have CNAME records.
Question and response
Question
dig zapistschmutz.eu. NS
Answer
zapistschmutz.eu. 5 NS leif.ns.cloudflare.com.
zapistschmutz.eu. 5 NS jasmine.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0