We've confirmed that all systems are back to normal with no customer impact as of 11/27, 16:30 UTC. Our logs show the incident started on 11/27, 16:15 UTC and that during the 15 minutes that it took to resolve the issue 5% of customers in South UK and East US regions might have experienced data access issues in OMS Portal for Log Analytics.
Root Cause: The failure was due to one of the dependent service.
Incident Timeline: 15 minutes - 11/27, 16:15 UTC through 11/27, 16:30 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.