ir.oi.com.br has no NS records.
NS records for this zone are defined at oi.com.br.
NS records for this zone are defined at oi.com.br.
Question and response
Question
dig sites-clients-08.mziq.com. NS
Answer
The response has no answer records.
Authority
mziq.com. 900 SOA ns-356.awsdns-44.com. awsdns-hostmaster.amazon.com. 1 7200 900 1209600 86400
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0