Apex domains cannot have CNAME records.
Question and response
Question
dig s-haendlerservice.de. NS
Answer
s-haendlerservice.de. 5 NS ns-cloud-c1.googledomains.com.
s-haendlerservice.de. 5 NS ns-cloud-c4.googledomains.com.
s-haendlerservice.de. 5 NS ns-cloud-c3.googledomains.com.
s-haendlerservice.de. 5 NS ns-cloud-c2.googledomains.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0