Final Update: Wednesday, 28 February 2019 03:08 UTC
We've confirmed that all systems are back to normal with no customer impact as of 02/28 02:38 UTC. Our logs show the incident started on 02/26, 21:00 UTC and that during the ~29hr 38m that it took to resolve the issue few customers would have experienced Notification miss from Azure Activity Log Alerts.
  • Root Cause: The failure was due to issues in one of our dependent services.
  • Incident Timeline: 29 Hours & 38 minutes - 02/26, 21:00 UTC through 02/28 02:38 UTC
We understand that customers rely on Azure Activity Log Alerts as a critical service and apologize for any impact this incident caused.
Update: Thursday, 28 February 2019 00:56 UTC

Root cause has been isolated to an issue with one of the dependent services which was impacting notification misses for Activity Log alerts. To address this issue we are rolling back the configuration changes. Some customers may experience notification miss from Activity log alerts and we estimate in next ~2 hours the notification miss issue to be addressed for all customers.
  • Work Around: NA
  • Next Update: Before 02/28 04:00 UTC

Initial Update: Wednesday, 27 February 2019 23:22 UTC

We are aware of Notification issues within Activity Log alerts and are actively investigating. Some customers may experience missing notification for the Activity Log Alerts.
  • Work Around: NA
  • Next Update: Before 02/28 01:30 UTC
We are working hard to resolve this issue and apologize for any inconvenience.