Apex domains cannot have CNAME records.
Question and response
Question
dig intern.globvill.de. NS
Answer
intern.globvill.de. 5 NS ns1.globvill.de.
intern.globvill.de. 5 NS ns3.globvill.ruhr.
intern.globvill.de. 5 NS ns2.globvill.de.
Authority
The response has no authority records.
Additional
ns1.globvill.de. 5 A 212.20.160.5
ns2.globvill.de. 5 A 212.20.191.5
ns1.globvill.de. 5 AAAA 2001:40b8:0:0:0:0:0:11
ns2.globvill.de. 5 AAAA 2001:40b8:0:0:0:0:0:12
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0