pgrp.itau.com.br has no NS records.
NS records for this zone are defined at itau.com.br.
NS records for this zone are defined at itau.com.br.
Question and response
Question
dig itau.envie.email. NS
Answer
The response has no answer records.
Authority
envie.email. 1800 SOA kim.ns.cloudflare.com. dns.cloudflare.com. 2397599076 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0