Microsoft Defender for Office 365: Admins can block external users in Microsoft Teams from Defender Portal

Security admins with Defender for Office 365 Plan 1 and above can block external users from sending messages, calls, meetings invitation over Microsoft Teams via the Tenant Allow Block List in Microsoft Defender portal. Updated January 28, 2026: We are pausing rollout at this time as we address an ongoing issue. We apologize for any inconvenience.

Added to roadmap: 12 dec 2025 | Last modified: 24 feb 2026

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