Apex domains cannot have CNAME records.
Question and response
Question
dig cablelink.at. NS
Answer
cablelink.at. 5 NS adns002.dc1.conova.com.
cablelink.at. 5 NS adns003.conova.at.
cablelink.at. 5 NS adns004.conova.at.
cablelink.at. 5 NS adns001.dc1.conova.com.
Authority
The response has no authority records.
Additional
adns001.dc1.conova.com. 5 A 217.196.144.130
adns002.dc1.conova.com. 5 A 217.196.145.10
adns003.conova.at. 5 A 213.153.32.230
adns004.conova.at. 5 A 80.80.241.12
adns001.dc1.conova.com. 5 AAAA 2a02:16a8:5404:106:0:0:0:130
adns002.dc1.conova.com. 5 AAAA 2a02:16a8:5404:107:0:0:0:10
adns003.conova.at. 5 AAAA 2a03:c400:11:ffff:0:0:0:230
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0