mtl.mailcloud.com.br has no NS records.
NS records for this zone are defined at mailcloud.com.br.
NS records for this zone are defined at mailcloud.com.br.
Question and response
Question
dig mtl.mailcloud.com.br. NS
Answer
The response has no answer records.
Authority
mailcloud.com.br. 1800 SOA kim.ns.cloudflare.com. dns.cloudflare.com. 2396385557 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0