Apex domains cannot have CNAME records.
Question and response
Question
dig hamsterbets.de. NS
Answer
hamsterbets.de. 5 NS ns1104.ui-dns.de.
hamsterbets.de. 5 NS ns1075.ui-dns.biz.
hamsterbets.de. 5 NS ns1042.ui-dns.com.
hamsterbets.de. 5 NS ns1046.ui-dns.org.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0