mx1.mailprovider.com has no NS records.
NS records for this zone are defined at mailprovider.com.
NS records for this zone are defined at mailprovider.com.
Question and response
Question
dig mx1.mailprovider.com. NS
Answer
The response has no answer records.
Authority
mailprovider.com. 1800 SOA everton.ns.cloudflare.com. dns.cloudflare.com. 2396867980 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0