Some users may experience intermittent errors or failures when accessing Exchange Online through REST APIs

Title: Some users may experience intermittent errors or failures when accessing Exchange Online through REST APIs

User impact: Users may experience intermittent errors or failures when accessing Exchange Online through REST APIs.

Current status: We've identified that a recent service change intended to optimize directory functionality may have introduced an issue with how Exchange Online Representational State Transfer (REST) API requests are processed, resulting in intermittent errors or failures. We're testing this theory by disabling the change in a portion of the affected environments and monitoring service telemetry to determine whether this action alleviates impact. If successful, we'll proceed with disabling the change throughout the remaining affected environments to fully remediate impact.

Scope of impact: Impact may occur intermittently for users attempting to access Exchange Online through REST APIs.

Next update by: Tuesday, October 27, 2026, at 7:30 PM UTC

Title: Some users may experience intermittent errors or failures when accessing Exchange Online through REST APIs

User impact: Users may experience intermittent errors or failures when accessing Exchange Online through REST APIs.

Current status: We're continuing to review service telemetry and recent service changes in an effort to isolate the source of this issue and determine an appropriate remediation action.

Scope of impact: Impact may occur intermittently for users attempting to access Exchange Online through REST APIs.

Next update by: Tuesday, October 27, 2026, at 5:30 PM UTC

Title: Some users may experience intermittent errors or failures when accessing Exchange Online through REST APIs

User impact: Users may experience intermittent errors or failures when accessing Exchange Online through REST APIs.

Current status: We're investigating an issue in which users may experience intermittent errors or failures when accessing Exchange Online through REST APIs. We're reviewing service telemetry to determine the underlying cause and identify the most effective remediation action. We'll provide an update within 30 minutes.