Apex domains cannot have CNAME records.
Question and response
Question
dig vivatecnologia.com.br. NS
Answer
vivatecnologia.com.br. 4 NS ns2.vivatecnologia.com.br.
vivatecnologia.com.br. 4 NS ns1.vivatecnologia.com.br.
Authority
The response has no authority records.
Additional
ns1.vivatecnologia.com.br. 4 A 170.81.100.19
ns2.vivatecnologia.com.br. 4 A 170.81.100.12
ns1.vivatecnologia.com.br. 4 AAAA 2804:376c:cafe:e:faca:0:0:3
ns2.vivatecnologia.com.br. 4 AAAA 2804:376c:aaaa:0:cccc:0:0:3335
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0