2688968 - Signature validation of SAML2Assertion failed - SAP BTP Neo environment

Application can not be reached in Neo environment through an SAML Identity Provider.

• An "HTTP Status 500 - An internal application error occurred" error is displayed on the screen after performing SSO, or the SSO process is in an infinite loop.
    
• The application log contains the following error:
   
  #ERROR#Authentication failed. Reason: Signature validation of SAML2Assertion failed. com.sap.security.saml2.lib.common.SAML2Exception: Signature not valid!
  
  
• The application log may contain following error instead:
  
  

  Caused by: com.sap.security.saml2.sp.sso.exception.BadCredentialsException: SAML2Response signature verification failed.
  ...
  Caused by: com.sap.security.saml2.lib.common.SAML2Exception: Certificate is expired (Certificate NotAfter: <expired validity date>)
  ... 
  Caused by: java.security.cert.CertificateExpiredException: NotAfter: <expired validity date>

  
  

SAP BTP, Neo environment

SAML, IDP, corporate IDP, HTTP Status 500, An internal application error occured, Authentication failed, Signature validation, SAML2Assertion failed, Caused by: com.sap.security.saml2.lib.common.SAML2Exception: Signature not valid!, CertificateExpiredException, SAML2Exception, Certificate is expired, NotAfter, CertificateExpiredException: NotAfter   , KBA , scp , sap cloud platform , BC-NEO-SEC-IAM , Authentication, Authorization(Cloud Platform Neo) , Problem