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