Apex domains cannot have CNAME records.
Question and response
Question
dig inwx.de. NS
Answer
inwx.de. 3 NS damon.ns.cloudflare.com.
inwx.de. 3 NS dell.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
damon.ns.cloudflare.com. 4 A 108.162.193.96
damon.ns.cloudflare.com. 4 A 172.64.33.96
damon.ns.cloudflare.com. 4 A 173.245.59.96
damon.ns.cloudflare.com. 4 AAAA 2606:4700:58:0:0:0:adf5:3b60
damon.ns.cloudflare.com. 4 AAAA 2803:f800:50:0:0:0:6ca2:c160
damon.ns.cloudflare.com. 4 AAAA 2a06:98c1:50:0:0:0:ac40:2160
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0