Apex domains cannot have CNAME records.
Question and response
Question
dig datalix.de. NS
Answer
datalix.de. 4 NS tia.ns.cloudflare.com.
datalix.de. 4 NS dean.ns.cloudflare.com.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0