Apex domains cannot have CNAME records.
Question and response
Question
dig kabsi.at. NS
Answer
kabsi.at. 5 NS radio.kabsi.at.
kabsi.at. 5 NS signal.kabsi.at.
Authority
The response has no authority records.
Additional
radio.kabsi.at. 5 A 195.202.128.3
signal.kabsi.at. 5 A 195.202.128.2
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0