Apex domains cannot have CNAME records.
Question and response
Question
dig weingaertner-it.de. NS
Answer
weingaertner-it.de. 2 NS dns10.weingaertner-it.de.
weingaertner-it.de. 2 NS name01.weingaertner-it.de.
Authority
The response has no authority records.
Additional
dns10.weingaertner-it.de. 2 A 193.32.222.35
name01.weingaertner-it.de. 2 A 92.60.37.108
dns10.weingaertner-it.de. 2 AAAA 2a0a:51c0:0:42:0:0:0:2
name01.weingaertner-it.de. 2 AAAA 2a03:4000:33:768:0:0:0:1
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0