Select 
SSL Decryption Settings to 
enable inspection of SSL/TLS handshakes when
            users navigate to websites over a decrypted HTTPS connection. The Content and Threat
            Detection (CTD) engine on the firewall will evaluate the contents of the handshake
            against Security policy rules, which enables the firewall to enforce the rules as early
            in the session as possible. You must have a URL Filtering subscription, configure either
                
SSL Forward Proxy or 
SSL Inbound Inspection, and block specific URL
            categories in your Security policy rules to use this feature. 
    
    URL Filtering response pages do not display for sites that are blocked during
                    SSL/TLS handshake inspection. After detecting traffic from blocked categories,
                    the firewall resets the HTTPS connection, ending the handshake and preventing
                    user notification by response page. Instead, the browser displays a standard
                    connection error message.