omx1.firstcloudsecurity.net has no MX records.
Question and response
Question
dig omx1.firstcloudsecurity.net. MX
Answer
The response has no answer records.
Authority
firstcloudsecurity.net. 300 SOA ns1.firstwave.com.au. admin.firstwave.com.au. 2017030224 3600 600 604800 3600
Additional
. 0 OPT ; payload 4096, xrcode 0, version 0, flags 0