Apex domains cannot have CNAME records.
Question and response
Question
dig compusoftinternet.com.br. NS
Answer
compusoftinternet.com.br. 5 NS b.dns.mantenedora.io.
compusoftinternet.com.br. 5 NS a.dns.mantenedora.io.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0