We've confirmed that all systems are back to normal with no customer impact as of 08/26, 20:00 UTC. Our logs show the incident started on 08/26, 17:50 UTC and that during the 2 hours 10 minutes that it took to resolve the issue ~8% of the customers using Log alerts which are configured in East US region might have experienced Alerting failure.
Root Cause: The failure was due to issues in one of our back-end services.
Incident Timeline: 2 Hours & 10 minutes - 08/26, 17:50 UTC through 08/26, 20:00 UTC
We understand that customers rely on Log Search Alerts as a critical service and apologize for any impact this incident caused.
Initial Update: Monday, 26 August 2019 18:52 UTC
We are aware of issues within Log Search Alerts and are actively investigating. Some customers may experience alerting failures in East US region.
Work Around: none
Next Update: Before 08/26 22:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -venkat