The following ports should be opened if the system does not work through the corporate firewall:
www.simplylookupadmin.co.uk port 80 (HTTP/HTTPS)
Also in the installed directory is a file called "RegServerProxySettings.xml", which allows your to set the address of your proxy server:
RegServerProxySettings.xml https://your_proxy_server:80
https://your_proxy_server:80