December 2021
16
Summary of Impact: Between 14:00 UTC and 17:30 UTC on 16 December 2021, a subset of users in North America may have experienced performance issues and timeout errors with Microsoft Graph APIs.
Preliminary Root Cause: We determined that the scaling out process was affected by an internal infrastructure issue leading to high CPU usage. This resulted in the performance issues and timeout errors with Microsoft Graph APIs.
Mitigation: To mitigate the issue we redistributed traffic to other healthy regions in North America.
Next steps: We will continue to investigate to establish the full root cause and prevent future occurrences. Stay informed about Azure service issues by creating custom service health alerts: https://aka.ms/ash-videos for video tutorials and https://aka.ms/ash-alerts for how-to documentation.