ns4.iagentedns.com.br has no CNAME records.
Question and response
Question
dig ns4.iagentedns.com.br. NS
Answer
The response has no answer records.
Authority
iagentedns.com.br. 2254 SOA ns1.iagente.net.br. hostmaster.iagentedns.com.br. 2023092201 10800 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0