mx.linje.dk has no NS records.
NS records for this zone are defined at linje.dk.
NS records for this zone are defined at linje.dk.
Question and response
Question
dig mx.linje.dk. NS
Answer
The response has no answer records.
Authority
linje.dk. 1800 SOA lucy.ns.cloudflare.com. dns.cloudflare.com. 2395210363 10000 2400 604800 1800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0