Apex domains cannot have CNAME records.
Question and response
Question
dig namesecure.de. NS
Answer
namesecure.de. 5 NS ns.europeandns.eu.
namesecure.de. 5 NS ns.europeandns.de.
namesecure.de. 5 NS ns.europeandns.net.
Authority
The response has no authority records.
Additional
ns.europeandns.de. 5 A 194.0.182.225
ns.europeandns.eu. 5 A 194.50.187.225
ns.europeandns.net. 5 A 193.227.117.225
ns.europeandns.de. 5 AAAA 2a04:2b00:14ee:0:0:0:0:225
ns.europeandns.eu. 5 AAAA 2a04:2b00:14dd:0:0:0:0:225
ns.europeandns.net. 5 AAAA 2a04:2b00:14cc:0:0:0:0:225
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0