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MC1200058 — Microsoft Defender for Office 365: Admins can block external users in Microsoft Teams from Defender Portal

MC1200058Microsoft Teams · Microsoft Defender XDRstayInformedUpdated: 24 January 2026

Starting mid-February 2026, admins can block external Microsoft Teams users via the Tenant Allow/Block List in the Microsoft Defender portal, controlling access and deleting existing communications. This applies to Teams and Defender XDR, with audit logging and limits of 4,000 domains and 200 emails blocked.

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Applies to: Microsoft Teams · Microsoft Defender XDR
Source: mc.merill.net — data via Merill Fernando's open archive (MIT).