We've confirmed that all systems are back to normal with no customer impact as of 04/20, 15:55 UTC. Our logs show the incident started on 04/20, 13:30 UTC and that during the 2 hour and 25 minutes that it took to resolve the issue some customers in West Europe region would have experienced intermittent query failures and issues in accessing their data on the Azure portal.
Root Cause: The failure was due to an issue with one of our backend services.
Incident Timeline: 2 Hour & 25 minutes - 04/20, 13:30 UTC through 04/20, 15:55 UTC
We understand that customers rely on Application Insights as a critical service and apologize for any impact this incident caused.