mx.xtra.co.nz has no NS records.
NS records for this zone are defined at xtra.co.nz.
NS records for this zone are defined at xtra.co.nz.
Question and response
Question
dig mx.xm.smxcloud.com. NS
Answer
The response has no answer records.
Authority
xm.smxcloud.com. 60 SOA ns1-05.azure-dns.com. hostmaster.smxemail.com. 1 3600 600 604800 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0