Azure Front Door - Connectivity Issues

Summary of impact: Between 06:48 and 11:17 UTC on 14 June 2022, a subset of customers experienced connectivity issues to Azure Front Door, which was also causing issues connecting to the Azure Portal. Retries would have succeeded for some impacted customers.Preliminary Root Cause: The Azure Front Door (AFD) service, which serves as the CDN for Azure Portal, experienced a brief unexpected surge in requests, causing connectivity issues for some customers. This appears to have caused an inbound traffic management and load balancing issue for Azure Front Door. Mitigation steps have been applied at both the Azure Front Door and Azure Portal level, and we can confirm the issues have been resolved as of 11:17 UTC. The majority of customers would have seen improvement in advance of the final mitigation time.Mitigation: AFD rebalanced traffic between environments, reducing error rates seen, and we monitored for an extended period to ensure that no further impact was observed.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.