The Federation Service encountered an error while loading the trust policy. An unexpected exception was encountered. If this ...

The Federation Service encountered an error while loading the trust policy. An unexpected exception was encountered. 

If this error occurs during startup of the Federation Service, the Federation Service will not be able to start and all requests to the Federation Service will fail until the configuration is corrected. If this error occurs while the Federation Service is running, the Federation Service will continue to use the last policy that was loaded successfully, and it will attempt to load the policy again in %1 minutes.
Retry period: %1 

User Action 
If this error persists, enable the AD FS troubleshooting log. 

Additional Data 
Exception information: 
%2