Consider the following scenario:
- You federate an application through a Windows Server 2012 R2-based AD FS (Active Directory Federation Services) instance that is an identity provider for the application.
- You define a Relying Party (RP) trust to the application on the AD FS instance. Additionally, you configure the application to send signed SAML requests that have percent-encoded characters in uppercase to the AD FS instance.
- You define a Claims Provider trust on the Windows Server 2012 R2-based AD FS instance to point to another AD FS instance that has an RP trust defined.
- You try to sign in to the application, and then the Home Realm Discovery page is displayed.
The Federation Service encountered an error while processing the SAML authentication request.