You are trying to run a newly introduced web-based VPM to edit or view policies on your ProxySG or ASG
"Failed to launch web-based VPM: The chosen editor is not supported by the reference device.
Do you want to launch the legacy VPM? "
Management Center version 184.108.40.206
ProxySG or ASG with SGOS versions prior to 220.127.116.11
Web-based VPM was introduced in SGOS 18.104.22.168. If your Proxy appliance is running a version prior to 22.214.171.124, the web-based VPM will not work. You can still use legacy VPM, with full functionality.
To take advantage of new web-based VPM, you will need to upgrade the SGOS firmware version on your Proxy to 126.96.36.199 or newer.