mailx.registro.br has no NS records.
NS records for this zone are defined at registro.br.
NS records for this zone are defined at registro.br.
Question and response
Question
dig mailx.registro.br. NS
Answer
The response has no answer records.
Authority
registro.br. 900 SOA a.dns.br. hostmaster.registro.br. 2026032000 1800 900 604800 900
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0