Apex domains cannot have CNAME records.
Question and response
Question
dig teol.net. NS
Answer
teol.net. 1 NS ns1.teol.net.
teol.net. 1 NS ns2.teol.net.
Authority
The response has no authority records.
Additional
ns1.teol.net. 1 A 81.93.64.1
ns2.teol.net. 1 A 81.93.64.9
ns1.teol.net. 1 AAAA 2a00:cb00:0:5:0:0:0:1
ns2.teol.net. 1 AAAA 2a00:cb00:0:5:0:0:0:9
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0