v5165.v51871eb6.use4.send.mailgun.net has no NS records.
NS records for this zone are defined at v51871eb6.use4.send.mailgun.net.
NS records for this zone are defined at v51871eb6.use4.send.mailgun.net.
Question and response
Question
dig v5165.v51871eb6.use4.send.mailgun.net. NS
Answer
The response has no answer records.
Authority
v51871eb6.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