mx02.movistar.com.ar has no NS records.
NS records for this zone are defined at movistar.com.ar.
NS records for this zone are defined at movistar.com.ar.
Question and response
Question
dig mx02.movistar.com.ar. NS
Answer
The response has no answer records.
Authority
movistar.com.ar. 600 SOA nsvel1a.tgt.net.ar. admindnsmovistar.telefonicamoviles.com.ar. 2016041677 1800 900 1209600 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0