Apex domains cannot have CNAME records.
Question and response
Question
dig edgetelecom.com.br. NS
Answer
edgetelecom.com.br. 4 NS ns2.braesp.net.br.
edgetelecom.com.br. 4 NS ns1.braesp.net.br.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0