Apex domains cannot have CNAME records.
Question and response
Question
dig rjtecnologia-pe.net.br. NS
Answer
rjtecnologia-pe.net.br. 5 NS ns1.rjtecnologia-pe.net.br.
rjtecnologia-pe.net.br. 5 NS ns2.rjtecnologia-pe.net.br.
Authority
The response has no authority records.
Additional
ns1.rjtecnologia-pe.net.br. 5 A 170.244.76.12
ns2.rjtecnologia-pe.net.br. 5 A 170.244.76.13
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0