Apex domains cannot have CNAME records.
Question and response
Question
dig dnswnd.de. NS
Answer
dnswnd.de. 5 NS ns-561.awsdns-06.net.
dnswnd.de. 5 NS ns-1793.awsdns-32.co.uk.
dnswnd.de. 5 NS ns-418.awsdns-52.com.
dnswnd.de. 5 NS ns-1367.awsdns-42.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0