The Federation Service has detected a discrepancy between its signing methods and its verification methods. If this condition ...

The Federation Service has detected a discrepancy between its signing methods and its verification methods. If this condition is caused by a change in trust policy, the Federation Service will continue to use the old trust policy until the condition is resolved. If this condition occurs at startup, the Federation Service will not be able to service requests until the condition is resolved. 
Signing certificate thumbprint: %1 

The certificate chain for the token-signing certificate cannot be verified. 
Native Error Code: %2 

User Action 
Make sure that the token-signing certificate matches one of the verification certificates in the trust policy. 

The native error code comes from CertGetCertificateChain or CertVerifyCertificateChainPolicy. Check the documentation to troubleshoot the error code, and take action accordingly. For example, if the error code is CERT_E_EXPIRED, the token-signing certificate has expired and must be replaced or renewed. If the error code is CRYPT_E_REVOCATION_OFFLINE, make sure that the revocation checking service is online, or disable revocation checking using the Active Directory Federation Services snap-in when necessary (Trust Policy Properties -> Verification Certificates -> Revocation Settings: choose None).