Microsoft 365 Alert – Service Degradation – Microsoft 365 suite – Some admins may be unable to view the tenant allow or block list in the Microsoft Defender XDR portal – RESOLVED

Announcements Sourav Nandi

09/09/2025 08:30:00 AM

NHSmail Reference: INC46624164

Microsoft Reference: MO1149866

Issue Status: RESOLVED

Issue Description: Some admins may be unable to view the tenant allow or block list in the Microsoft Defender XDR portal.

More info: When admins attempted to view the tenant allow or block list, they may have received an error that states: “Failed to load, try again later.”

Current Update: 09/09/2025 08:30:00 AM – Microsoft have deployed their fix to remove the misconfiguration and confirmed through service telemetry that the impact is remediated.

Scope of impact: Some admins attempting to view or adjust the tenant allow or block list may have been impacted.

Root cause: A recent service change contained a misconfiguration that caused impact.

Next steps: Microsoft are reviewing their service change testing and validation procedures to identify and prevent similar misconfigurations in deployments moving forward.