mx.queuemanager.net has no NS records.
NS records for this zone are defined at queuemanager.net.
NS records for this zone are defined at queuemanager.net.
Question and response
Question
dig mx.queuemanager.net. NS
Answer
The response has no answer records.
Authority
queuemanager.net. 3600 SOA dns.queuemanager.net. hostmaster.queuemanager.net. 1891385828 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0