We've confirmed that all systems are back to normal with no customer impact as of 10/22, 04:30 UTC. Our logs show the incident started on 10/21, 23:20 UTC and that during the 5 hours 10 minutes that it took to resolve the issue customers would have experienced Data latency, Data access and Alerting failures in West Europe region.
Root Cause: The failure was due to connections getting timed out with Azure storage in West Europe region.
Incident Timeline: 5 Hours & 10 minutes - 10/21, 23:20 UTC through 10/22, 04:30 UTC
We understand that customers rely on Application Insights as a critical service and apologize for any impact this incident caused.
Update: Tuesday, 22 October 2019 04:56 UTC
We continue to investigate issues within Application Insights. Root cause is not fully understood at this time. Some customers continue to experience Data access and Data latency issue in West Europe region. We are working to establish the start time for the issue, initial findings indicate that the problem began at 10/22 ~00:10 UTC. We currently have no estimate for resolution.