Final Update: Wednesday, 18 December 2019 20:52 UTC
We've confirmed that all systems are back to normal with no customer impact at present. Our logs show the incident started on 12/18, 18:00 UTC and that during the 1 hour 15 minutes that it took to resolve the issue some customers experienced data access and alerting failures.
Root Cause: The failure was due to memory issue in underlying infrastructure.
Incident Timeline: 1 Hour & 15 minutes - 12/18, 18:00 UTC through 12/18, 19:15 UTC
We understand that customers rely on Azure Monitor as a critical service and apologize for any impact this incident caused.
Initial Update: Wednesday, 18 December 2019 18:38 UTC
We are aware of issues within Azure Monitor and are actively investigating. Some customers may experience query and alerting failures against the data stored in West Europe region.
Next Update: Before 12/18 21:00 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Arvind