imx.firstcloudsecurity.net has no CNAME records.
Question and response
Question
dig imx.firstcloudsecurity.net. NS
Answer
The response has no answer records.
Authority
firstcloudsecurity.net. 17 SOA ns1.firstwave.com.au. admin.firstwave.com.au. 2017030224 3600 600 604800 3600
Additional
. 0 OPT ; payload 1232, xrcode 0, version 0, flags 0