mx.jm.jangomail.com has no NS records.
NS records for this zone are defined at jangomail.com.
NS records for this zone are defined at jangomail.com.
Question and response
Question
dig mx.jm.jangomail.com. NS
Answer
The response has no answer records.
Authority
jangomail.com. 180 SOA ns11.constellix.com. dns.constellix.com. 2015010465 43200 3600 1209600 180
Additional
. 0 OPT ; payload 1280, xrcode 0, version 0, flags 0