You are trying to enable SSL Interception (on the Visual Policy Manager, also known as VPM, on the SSL Interception layer) with the Web Security Service (for policies applied only to Web Security Service) or Universal (policies applied to both Appliance and WSS) enforcement, but you are receiving an error. It only seems to work from Appliance enforcement.
"The detect_protocol property is enabled on most of the WSS services. Please ensure that WSS service configuration matches your policy expectations". (The SSL Intercept. an action is shown in red)."
The policy classification is out of date in the reference ProxySG