First published on MSDN on Dec 01, 2018
Final Update: Saturday, 01 December 2018 01:58 UTC

We've confirmed that all systems are back to normal with no customer impact as of 12/01, 01:30 UTC. Our logs show the incident started on 11/30, 12:30 UTC and that during the 13 hours that it took to resolve the issue all the customers might have seen delays in classic alerting process in Application Insights.
Root Cause: The failure was due to issue in one of our back end services.
Incident Timeline: 13 Hours & 0 minutes - 11/30, 12:30 UTC through 12/01, 01:30 UTC
We understand that customers rely on Application Insights as a critical service and apologize for any impact this incident caused.

-Sindhu
Initial Update: Saturday, 01 December 2018 00:47 UTC

We are aware of issues within Application Insights and are actively investigating. All customers might have seen delays in classic alerting process in Application Insights.
Work Around: None
Next Update: Before 12/01 03:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience.

-Sindhu