a60.a0ece303.use4.send.mailgun.net has no NS records.
NS records for this zone are defined at a0ece303.use4.send.mailgun.net.
NS records for this zone are defined at a0ece303.use4.send.mailgun.net.
Question and response
Question
dig a60.a0ece303.use4.send.mailgun.net. NS
Answer
The response has no answer records.
Authority
a0ece303.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