firefox issue with https sites

Question

We are running web proxy appliance with HTTPS SCANNING DISABLED , however we still have issue with firefox complaining for SWA certificate. 
 I thought that this would be a normal behavior with HTTPS scanning enabled , but I don't understand why it's happening also with it disabled. 
 For example we don't have the same issue with UTM 9 or other vendor's Solutions

Red_Warrior · Answer

Hi Stefano, 
 The reason you are getting the certificate errors is because all of the internal pages the appliance stores are on an https server. 
 for example, the block page, captive portal, policy violation and other warning pages. 
 so the appliance presents its certificate so that it can show you the warning page. 
 
 In the case of https scanning then every https page would present the user with the appliance certificate. All sites would also appear to be signed by the Sophos PLC. In either case it's best to push out the appliance certificate via gpo to avoid all of the ssl warnings.