March 2022
16
Summary of Impact: Between 09:13 and 10:22 UTC on March 16, 2022, end-users of customers using Azure Active Directory B2C may have experienced errors and timeouts when attempting to sign in or sign up. Retry attempts were likely to succeed during this incident
Root Cause: The service experienced a significant increase in workload in the affected region during a planned maintenance operation. As a result, a subset of sign-in requests was queued up by the system, which increased processing time, and in some cases sign-in attempts by end-users may have timed out.
Mitigation: The service automatically scaled up compute resources in response to the increase in workload, which provided partial relief. In addition, we rerouted subsets of the workload to alternate capacity to achieve complete mitigation.
Next Steps: We apologize for the impact to affected customers. We are continuously taking steps to improve the Microsoft Azure Platform and our processes to help ensure such incidents do not occur in the future. In this case, this includes (but is not limited to):
- Improve planned maintenance Standard Operating Procedures (SOP) by pre-provisioning of additional capacity to affected regions to help handle unanticipated workload.
- Improve planned maintenance SOP to include pro-active assessment of similar pre-provisioning in other regions beyond the affected region for the service.
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