In SharePoint Foundation 2010, you may experience one or more of the following symptoms:
- You will see the message "The requested service, 'http://localhost:32843/SecurityTokenServiceApplication/securitytoken.svc/actas' could not be activated" in the application event logs of the servers.
- Users will not be able to log in to SharePoint sites that are using claims authentication.
- SharePoint internal operations that rely on claims authentication will not function correctly.
This problem can be caused if one or more of the following conditions are true:
- The .NET trust level for the secure token service is not set to "Full" in IIS.
- The application pool for the secure token service is not started or is using invalid credentials.
In order to resolve this problem, you can try one of the following possible solutions:
- From IIS Manager, click on the SecureTokenServiceApplication. In the "Features View", double click on .NET Trust Levels. Ensure that the trust level is set to "Full"
- From IIS Manager, ensure that the application pool for SecureTokenServiceApplication is running. By default, the name of the application pool is SecureTokenServiceApplicationPool.