mail.rni.com.pk has no NS records.
NS records for this zone are defined at rni.com.pk.
NS records for this zone are defined at rni.com.pk.
Question and response
Question
dig mail.rni.com.pk. NS
Answer
The response has no answer records.
Authority
rni.com.pk. 1800 SOA merlin.ns.cloudflare.com. dns.cloudflare.com. 2397150953 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0