v510.v524e8ec4.use4.send.mailgun.net has no NS records.
NS records for this zone are defined at v524e8ec4.use4.send.mailgun.net.
NS records for this zone are defined at v524e8ec4.use4.send.mailgun.net.
Question and response
Question
dig v510.v524e8ec4.use4.send.mailgun.net. NS
Answer
The response has no answer records.
Authority
v524e8ec4.use4.send.mailgun.net. 300 SOA ns-cloud-a1.googledomains.com. cloud-dns-hostmaster.google.com. 1 21600 3600 259200 300
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0