mx42.allin.com.br has no NS records.
NS records for this zone are defined at allin.com.br.
NS records for this zone are defined at allin.com.br.
Question and response
Question
dig mx42.allin.com.br. NS
Answer
The response has no answer records.
Authority
allin.com.br. 1800 SOA henrik.ns.cloudflare.com. dns.cloudflare.com. 2396495685 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0