Apex domains cannot have CNAME records.
Question and response
Question
dig snw.at. NS
Answer
snw.at. 5 NS ns1.stww.at.
snw.at. 5 NS ns2.stww.at.
snw.at. 5 NS ns3.stww.at.
Authority
The response has no authority records.
Additional
ns1.stww.at. 5 A 83.219.160.70
ns2.stww.at. 5 A 83.219.161.70
ns3.stww.at. 5 A 185.106.190.5
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0