v5129.v54f91261.use4.send.mailgun.net has no NS records.
NS records for this zone are defined at v54f91261.use4.send.mailgun.net.
NS records for this zone are defined at v54f91261.use4.send.mailgun.net.
Question and response
Question
dig v5129.v54f91261.use4.send.mailgun.net. NS
Answer
The response has no answer records.
Authority
v54f91261.use4.send.mailgun.net. 300 SOA ns-cloud-e1.googledomains.com. cloud-dns-hostmaster.google.com. 1 21600 3600 259200 300
Additional
. 0 OPT ; payload 512, xrcode 0, version 0, flags 0