Apex domains cannot have CNAME records.
Question and response
Question
dig iagente.net.br. NS
Answer
iagente.net.br. 4 NS ns2.iagente.net.br.
iagente.net.br. 4 NS ns5.iagente.net.br.
iagente.net.br. 4 NS ns3.iagente.net.br.
iagente.net.br. 4 NS ns1.iagente.net.br.
iagente.net.br. 4 NS ns4.iagente.net.br.
Authority
The response has no authority records.
Additional
ns1.iagente.net.br. 4 A 177.85.210.12
ns2.iagente.net.br. 4 A 177.85.210.13
ns3.iagente.net.br. 4 A 177.85.210.14
ns4.iagente.net.br. 4 A 159.203.170.213
ns5.iagente.net.br. 4 A 159.89.141.150
ns1.iagente.net.br. 4 AAAA 2804:6f8:0:1:177:85:210:12
ns2.iagente.net.br. 4 AAAA 2804:6f8:0:1:177:85:210:13
ns3.iagente.net.br. 4 AAAA 2804:6f8:0:1:177:85:210:14
ns4.iagente.net.br. 4 AAAA 2604:a880:800:14:0:0:6d52:f000
ns5.iagente.net.br. 4 AAAA 2604:a880:2:d1:0:0:3712:3000
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0