Apex domains cannot have CNAME records.
Question and response
Question
dig sydantenn.net. NS
Answer
sydantenn.net. 5 NS ns1.teleservice.net.
sydantenn.net. 5 NS ns2.teleservice.net.
Authority
The response has no authority records.
Additional
ns1.teleservice.net. 1 AAAA 2a02:80:3ffe:0:0:0:0:10
ns2.teleservice.net. 1 AAAA 2a02:80:3ffd:0:0:0:0:10
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0