Apex domains cannot have CNAME records.
Question and response
Question
dig comteam.at. NS
Answer
comteam.at. 5 NS ns1.comteam.at.
comteam.at. 5 NS ns2.comteam.at.
Authority
The response has no authority records.
Additional
ns1.comteam.at. 5 A 192.174.68.100
ns2.comteam.at. 5 A 176.97.158.100
ns1.comteam.at. 5 AAAA 2001:67c:1bc:0:0:0:0:100
ns2.comteam.at. 5 AAAA 2001:67c:10b8:0:0:0:0:100
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0