Microsoft 365 Alert – Service Degradation – Power BI – Users may have experienced login failures when connecting to their Data Warehouse or SQL Endpoint in Microsoft Fabric – RESOLVED

09/05/2026 09:46:00 AM

NHSmail Reference: INC46845155

Microsoft Reference: PB1383683

Issue Status: RESOLVED

Issue Description: Users may have experienced login failures when connecting to their Data Warehouse or SQL Endpoint in Microsoft Fabric.

More info: Impacted users may have received the following error message:

“An internal error happened due to failed runtime assertion: Moniker not present in the Moniker Manager.”

Final Update: 09/05/2026 09:46:00 AM – Microsoft has  determined that a portion of the infrastructure supporting access to Fabric Data Warehouses and SQL Endpoints in the Southern UK region was not performing as expected, resulting in intermittent connection failures. We’ve determined that the issue was transient and resolved itself.

Scope of impact: Your organization was affected by this event, and some users whose Fabric capacities are hosted in the Southern UK region, attempting to connect to their Data Warehouse or SQL Endpoint in Microsoft Fabric, may have been impacted.

Root cause: A section of infrastructure supporting access to Fabric Data Warehouses and SQL Endpoints in the Southern UK region wasn’t performing as expected, resulting in connection failures.

Next Steps: Microsoft will continue to closely monitor the affected environment to ensure the service remains healthy.