Apex domains cannot have CNAME records.
Question and response
Question
dig german-local.net. NS
Answer
german-local.net. 5 NS ns2.purteldns.de.
german-local.net. 5 NS ns1.purteldns.de.
Authority
The response has no authority records.
Additional
ns1.purteldns.de. 5 A 185.39.85.4
ns2.purteldns.de. 5 A 185.39.86.4
ns1.purteldns.de. 5 AAAA 2a01:41e0:110:0:0:0:0:4
ns2.purteldns.de. 5 AAAA 2a01:41e0:10:0:0:0:0:4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0