We've confirmed that all systems are back to normal with no customer impact as of 03/30 03:00 UTC. Our logs show the incident started on 03/29, 18:00 UTC and that during the 9 hours that it took to resolve the issue some customers using Azure Monitor experienced issues with delay in Activity Logs and also experienced issues with delayed Activity Log Alerts.
Root Cause: The failure was due to issues with one of the backend services.
Incident Timeline: 9 Hours - 03/29, 18:00 UTC through 03/30 03:00 UTC
We understand that customers rely on Activity Log Alerts as a critical service and apologize for any impact this incident caused.
Initial Update: Monday, 29 March 2021 23:23 UTC
We are aware of issues within Activity Log Alerts and are actively investigating. Some customers using Azure Monitor may experience issues with delay in Activity Logs and also experience issues with delay in Activity Log Alerts.
Next Update: Before 03/30 03:30 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Jayadev