Apex domains cannot have CNAME records.
Question and response
Question
dig allrede.tec.br. NS
Answer
allrede.tec.br. 5 NS ns2.allrede.tec.br.
allrede.tec.br. 5 NS ns1.allrede.tec.br.
Authority
The response has no authority records.
Additional
ns1.allrede.tec.br. 5 A 170.238.52.41
ns2.allrede.tec.br. 5 A 179.125.47.251
ns1.allrede.tec.br. 5 AAAA 2804:8aa4:81c:1:0:0:0:41
ns2.allrede.tec.br. 5 AAAA 2804:104c:2c00:c000:a06a:28ff:fe52:4cc4
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0