Error message
The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in a Faulted state.
This is a general message that you can get for a number of reasons. If you get this message then browse the config or cache service and run the asmx to get a more specific error.
HTTPS site
You will see this message display when you set the site to HTTPS in Server Manager but you have not updated the DefaultSPFServerURL in the server site's settings to include HTTPS. The error in the log file gives further detail:
Failed to connect to the default SPFServer specified in the configuration file ---> SPF.Server.SPFException: Failed to connect to default SPFServer at 'http://localhost/SPFServer/ServerRequest.asm'.
Solution
When you set a site to include HTTPS, you must change the DefaultSPFServerURL in the server site's settings in Server Manager to HTTPS.