Apex domains cannot have CNAME records.
Question and response
Question
dig foxserv.de. NS
Answer
foxserv.de. 1 NS ns1.fuchsdeife.de.
foxserv.de. 1 NS h2969901.stratoserver.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0