Final Update: Tuesday, 18 January 2022 15:16 UTCWe've confirmed that all systems are back to normal with no customer impact as of 01/18, 13:30 UTC. Our logs show the incident started on 01/18, 13:00 UTC and that during the 30 minutes that it took to resolve the issue some of the customers using Log Analytics or Azure Sentinel in South UK region may have experienced issues accessing data as well as missed or delayed Log Search alerts.
- Root Cause: We determined that instances of a backend service became unhealthy, preventing these requests from completing.
- Incident Timeline: 30 minutes - 01/18, 13:00 UTC through 01/18, 13:30 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.-Surya 
