ns1.auth-dns.com has no MX records.
Question and response
Question
dig ns1.auth-dns.com. MX
Answer
The response has no answer records.
Authority
auth-dns.com. 14400 SOA ns0.dmpriest.net.uk. root.dmpriest.com. 2025022703 7200 3600 2419200 14400
Additional
. 0 OPT ; payload 1400, xrcode 0, version 0, flags 0