We've confirmed that all systems are back to normal with no customer impact as of 01/11, 22:50 UTC. Our logs show the incident started on 01/11, 14:00 UTC and that during the 8 hours and 50 minutes that it took to resolve the issue customers experienced issues with creating or updating metric alert rules from Azure Portal, ARM Templates or Azure CLI.
Root Cause: The failure was due to one of the backend services.
Incident Timeline: 8 Hours & 50 minutes - 01/11, 14:00 UTC through 01/11, 22:50 UTC
We understand that customers rely on Metric Alerts as a critical service and apologize for any impact this incident caused.