mx2.nz.smxemail.com has no NS records.
NS records for this zone are defined at smxemail.com.
NS records for this zone are defined at smxemail.com.
Question and response
Question
dig mx2.nz.smxemail.com. NS
Answer
The response has no answer records.
Authority
smxemail.com. 60 SOA ns1-03.azure-dns.com. hostmaster.smxemail.com. 392 3600 600 604800 60
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0