Problem

Azure AD authentication method stops working and following error message is seen in diag log when authentication is interrupted:

protocol [xxx.xxx.xxx.xxx] MessageServer.frontChannelService: com.ubisecure.saml2.core.SAMLValidationException: SignatureValidator: urn:oasis:names:tc:SAML:2.0:status:Requester, urn:oasis:names:tc:SAML:2.0:status:RequestDenied: com.ubisecure.saml.core.SignatureIntegrityException: Signature: KeyInfo contains unknown public key.

Possible Cause

The certificate Azure AD generates has expired or has been updated.

Solution

Upload new federation metadata to the method and save the change.