mx.hostedemail.com has no NS records.
NS records for this zone are defined at hostedemail.com.
NS records for this zone are defined at hostedemail.com.
Question and response
Question
dig mx.hostedemail.com. NS
Answer
The response has no answer records.
Authority
hostedemail.com. 300 SOA ns1.mdnsservice.com. hostmaster.mdnsservice.com. 2800684411 10001 7200 2419200 300
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0