The communication object, System.ServiceModel.Channels.ServiceChannel, cannot be used for communication because it is in the Faulted state.
In my case the reason was some wrong certificate that could not be loaded. I found out about it from the Event Viewer, under System:
A fatal error occurred when attempting to access the TLS server credential private key. The error code returned from the cryptographic module is 0x8009030D. The internal error state is 10001.