We've confirmed that all systems are back to normal with no customer impact as of 05/12, 19:48 UTC. Our logs show the incident started on 05/12, 19:11 UTC and that during the 37 minutes that it took to resolve the issue some of the customers using Log Analytics in North Central US Region may have experienced issues accessing data as well as missed or delayed Alerts.
Root Cause: The failure was due to issues with one of the backend Services.
Incident Timeline: 37 minutes - 05/12, 19:11 UTC through 05/12, 19:48 UTC
We understand that customers rely on Azure Log Analytics as a critical service and apologize for any impact this incident caused.