Apex domains cannot have CNAME records.
Question and response
Question
dig avato.com.br. NS
Answer
avato.com.br. 5 NS nameserver2.avato.com.br.
avato.com.br. 5 NS nameserver1.avato.com.br.
Authority
The response has no authority records.
Additional
nameserver1.avato.com.br. 5 A 177.36.33.226
nameserver2.avato.com.br. 5 A 177.36.33.235
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0