We've confirmed that all systems are back to normal with no customer impact as of 03/23, 19:50 UTC. Our logs show the incident started on 03/23, 18:35 UTC and that during the 1 hour and 15 minutes that it took to resolve the issue some customers in East US Region experienced issues with query failures and possible misfired alerts.
Root Cause: The failure was due to issues with one of the backend services.
Incident Timeline: 1 Hour & 15 minutes - 03/23, 18:35 UTC through 03/23, 19:50 UTC
We understand that customers rely on Application Insights as a critical service and apologize for any impact this incident caused.
Initial Update: Monday, 23 March 2020 19:42 UTC
We are aware of issues within Application Insights and are actively investigating. Some customers may experience query failures, Issues with false/incorrect alerts in East US region.
Next Update: Before 03/24 00:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Jayadev