We've confirmed that all systems are back to normal with no customer impact as of 1/26, 03:01 UTC. Our logs show the incident started on 1/25, 22:00 UTC and that during the approximately 5 hours that it took to resolve the issue 5608 customers will not be able to see (public preview) custom metrics between the start and end times of the incident.
Root Cause: The failure was due to a backend cluster becoming unhealthy.
Incident Timeline: 5 Hours & 1 minute - 1/25, 22:00 UTC through 1/26, 03:01 UTC
We understand that customers rely on Application Insights as a critical service and apologize for any impact this incident caused.
Initial Update: Friday, 25 January 2019 23:34 UTC
We are aware of issues within Application Insights and are actively investigating. Some customers may experience Data Gaps in their custom metrics originating from MDM beginning at 22:00 UTC.
Work Around: No current workaround
Next Update: Before 01/26 04:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience.