Apex domains cannot have CNAME records.
Question and response
Question
dig inova.net. NS
Answer
inova.net. 4 NS ns2.penso.com.br.
inova.net. 4 NS ns1.penso.com.br.
Authority
The response has no authority records.
Additional
ns1.penso.com.br. 4 A 200.219.235.30
ns2.penso.com.br. 4 A 201.20.9.69
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0