Final Update: Wednesday, 27 January 2021 10:28 UTC
We've confirmed that all systems are back to normal with no customer impact as of 01/27, 10:00 UTC. Our logs show the incident started on 01/27, 09:15 UTC and that during the 45 minutes that it took to resolve the issue some of customers may have received errors when accessing alerts. The alerts notifications were not impacted.
Root Cause: We determined that a recent deployment task impacted instances of the backend service which became unhealthy, causing these errors.
Incident Timeline: 45 minutes - 01/27, 09:15 UTC through 01/27, 10:00 UTC
We understand that customers rely on Azure Monitor as a critical service and apologize for any impact this incident caused.