Apex domains cannot have CNAME records.
Question and response
Question
dig novaoi.com.br. NS
Answer
novaoi.com.br. 5 NS ns2.srv.clusterdns.top.
novaoi.com.br. 5 NS ns1.srv.clusterdns.top.
Authority
The response has no authority records.
Additional
ns1.srv.clusterdns.top. 5 A 108.181.69.48
ns2.srv.clusterdns.top. 5 A 5.161.64.126
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0