mx.trueheart.store has no NS records.
NS records for this zone are defined at trueheart.store.
NS records for this zone are defined at trueheart.store.
Question and response
Question
dig mx.trueheart.store. NS
Answer
The response has no answer records.
Authority
trueheart.store. 3600 SOA dns.trueheart.store. hostmaster.trueheart.store. 1576710481 43200 3600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0