Apex domains cannot have CNAME records.
Question and response
Question
dig euroghost.de. NS
Answer
euroghost.de. 5 NS ns3.ghostgate.de.
euroghost.de. 5 NS ns1.ghostgate.de.
euroghost.de. 5 NS ns2.ghostgate.de.
Authority
The response has no authority records.
Additional
ns1.ghostgate.de. 2 A 5.231.78.7
ns2.ghostgate.de. 2 A 5.231.78.8
ns3.ghostgate.de. 2 A 5.230.26.24
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0