We've confirmed that all systems are back to normal with no customer impact as of 04/04, 03:05 UTC. Our logs show the incident started on 04/04, 02:25 UTC and that during the 40 minutes that it took to resolve the issue some customers in South UK Region experienced issues with query failures and failed alerting.
Root Cause: The failure was due to issues with one of the backend services.
Incident Timeline: 40 minutes - 04/04, 02:25 UTC through 04/04, 03:05 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.
Initial Update: Saturday, 04 April 2020 03:04 UTC
We are aware of issues within Log Analytics and are actively investigating. Some customers in South UK Region may experience issues with query failures and failed alerting.
Work Around: none
Next Update: Before 04/04 07:30 UTC
We are working hard to resolve this issue and apologize for any inconvenience. -Jayadev