mta.hosts.net.nz has no MX records.
Question and response
Question
dig mta.hosts.net.nz. MX
Answer
The response has no answer records.
Authority
hosts.net.nz. 28800 SOA ns1.hosts.net.nz. hostmaster.freeparking.co.nz. 2880955791 86400 7200 3600000 28800
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0