Apex domains cannot have CNAME records.
Question and response
Question
dig gamerica.com.br. NS
Answer
gamerica.com.br. 1 NS ns10.ovh.ca.
gamerica.com.br. 1 NS dns10.ovh.ca.
Authority
The response has no authority records.
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0