Apex domains cannot have CNAME records.
Question and response
Question
dig ops.nic.at. NS
Answer
ops.nic.at. 5 NS sec1.rcode0.net.
ops.nic.at. 5 NS sec2.rcode0.net.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0