Apex domains cannot have CNAME records.
Question and response
Question
dig virehost.com.br. NS
Answer
virehost.com.br. 1 NS ns2.virehost.com.br.
virehost.com.br. 1 NS ns1.virehost.com.br.
Authority
The response has no authority records.
Additional
ns1.virehost.com.br. 1 A 162.214.193.90
ns2.virehost.com.br. 1 A 162.214.193.239
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0