3694349 - AADSTS700021: Client assertion application identifier doesn't match 'client_id' parameter

• Application authentication is configured with SAP Cloud Identity Services as proxy and Microsoft Entra ID as Corporate IdP.
  
  
• Microsoft Entra ID is configured with OpenID Connect (OIDC) protocol.
  
  
• During the validation step in the OpenID configuration tab, the following error is seen: 
  "Failed to receive tokens from URI [https://login.microsoftonline.com/.../oauth2/v2.0/token]. Received response error [401 Unauthorized: "{"error":"invalid_client","error_description":"AADSTS700021: Client assertion application identifier doesn't match 'client_id' parameter. Review the documentation at https://learn.microsoft.com/entra/identity-platform/certificate-credentials 

• SAP Cloud Identity Services
• Microsoft Entra ID

OIDC, Azure, IdP, Ms Entra, OpenID, Identity Provider, IAS, IDS, 401, Unauthorized, AADSTS700021, Client ID, invalid_client , KBA , BC-IAM-OID , OIDC/OAUTH2 component in SAP Cloud Identity Services , Problem