Oracle IAM Upgrade (IDCS) Authentication Failure Post IAM Upgrade – Fusion SaaS REST APIs Impacted

Summary:

Following a recent Oracle IAM (IDCS) upgrade in our Non-Production environment, we are experiencing authentication failures when accessing Oracle Fusion SaaS REST APIs.

Multiple integrations (including Postman-based API testing and Entra ID federated authentication flows) are failing to obtain tokens from the Oracle IAM OAuth2 endpoint.

Post IAM upgrade, API calls from Postman (and integration flows) are failing during authentication with the following error:

{"error":"invalid_grant","error_description":"Invalid audience in user assertion."}

This issue is impacting our ability to authenticate and consume Fusion SaaS REST APIs.

Current Setup

• Identity Provider: Microsoft Entra ID (Azure AD)
• Service Provider: Oracle IAM / IDCS