In most cases, softphones like X-Lite etc require that the port number be included at the end of the IP address you are registering to.
For example, you should add a colon and then the SIP port number at the end of our server address ...
sip.ezytel.com.au:5060
or
pbx.ezytel.com.au:5060
The same is true if you're adding the SIP proxy server address ...
proxy.ezytel.com.au:5070 (note the different port number)