Apex domains cannot have CNAME records.
Question and response
Question
dig vc-cc.de. NS
Answer
vc-cc.de. 5 NS ns02.vcvn.de.
vc-cc.de. 5 NS ns01.vcvn.de.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0