Apex domains cannot have CNAME records.
Question and response
Question
dig xinon.at. NS
Answer
xinon.at. 1 NS web6.xinon.at.
xinon.at. 1 NS ns3.xinon.at.
Authority
The response has no authority records.
Additional
ns3.xinon.at. 1 A 5.206.204.80
web6.xinon.at. 1 A 195.191.252.50
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0