mx.hostns.io has no NS records.
NS records for this zone are defined at hostns.io.
NS records for this zone are defined at hostns.io.
Question and response
Question
dig mx.hostns.io. NS
Answer
The response has no answer records.
Authority
hostns.io. 1800 SOA justin.ns.cloudflare.com. dns.cloudflare.com. 2397222187 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0