Microsoft 365 Alert – Service Degradation – Microsoft Defender XDR – Some users may have encountered delays of up to 3 hours for telemetry in Microsoft Defender for Endpoint – RESOLVED

10/08/2026 09:51:00 AM

NHS.net Connect Reference: INC46904459

Microsoft Reference: DZ1451367

Issue Status: RESOLVED

Issue Description: Some users may have encountered delays of up to 3 hours for telemetry in Microsoft Defender for Endpoint.

Final Update: 10/08/2026 09:51:00 AM –Microsoft has identified that a section of networking infrastructure, responsible for processing Microsoft Defender for Endpoint telemetry, began performing below acceptable performance thresholds and caused impact. They have applied performance and traffic optimizations on the infrastructure and confirmed impact is no longer occurring after a period of monitoring.

Scope of impact: Some users with Copilot licenses encountered errors when attempting to send prompts through Copilot Chat while the “Web” content toggle was enabled.

Root cause: A recent change intended to improve how Copilot requests were routed unexpectedly sent some requests through an incompatible service path, resulting in the impact.

Next steps: Microsoft is reviewing their validation and updating procedures