Apex domains cannot have CNAME records.
Question and response
Question
dig webgenium.com.br. NS
Answer
webgenium.com.br. 5 NS ns02.webgenium.com.br.
webgenium.com.br. 5 NS ns01.webgenium.com.br.
Authority
The response has no authority records.
Additional
ns01.webgenium.com.br. 5 A 177.66.207.201
ns02.webgenium.com.br. 5 A 23.23.50.189
ns01.webgenium.com.br. 5 AAAA 2804:c18:eebe:207:0:0:0:201
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0