Apex domains cannot have CNAME records.
Question and response
Question
dig keysaturn122.de. NS
Answer
keysaturn122.de. 5 NS ns.keysaturn122.de.
keysaturn122.de. 5 NS ns2.keysaturn122.de.
Authority
The response has no authority records.
Additional
ns.keysaturn122.de. 5 A 95.169.160.9
ns2.keysaturn122.de. 5 A 62.141.49.4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0