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.
Roadmap › 542189
Microsoft Defender for Office 365: Admins can block external users in Microsoft Teams from Defender Portal
- General availability
- 2026-02
- Preview
- —
- Added
- 12 Dec 2025
- Last modified
- 24 Feb 2026 00:15 UTC
- First archived
- 25 Aug 2026
- Release rings
- General Availability
- Clouds
- Worldwide (Standard Multi-Tenant)