Apex domains cannot have CNAME records.
Question and response
Question
dig vrmd.de. NS
Answer
vrmd.de. 5 NS ns1.variomedia.de.
vrmd.de. 5 NS ns2.variomedia.de.
Authority
The response has no authority records.
Additional
ns1.variomedia.de. 5 A 185.95.96.53
ns2.variomedia.de. 5 A 185.95.98.53
ns1.variomedia.de. 5 AAAA 2a00:1c3e:96:0:0:0:0:53
ns2.variomedia.de. 5 AAAA 2a00:1c3e:98:0:0:0:0:53
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0