Invitations are blocked for this directory due to suspicious activity - request to unblock B2B invitations

Yannis Bouhamou 0 Reputation points
2026-06-15T09:49:21.6566667+00:00

Hello,
Our tenant is blocked from sending B2B guest invitations. All invitations — via Microsoft Graph (POST /v1.0/invitations) and the Azure portal — now fail with: "Invitations are blocked for this directory due to suspicious activity.
Please contact Microsoft support for help." (HTTP 403 Forbidden) Context: we are onboarding a small number of external guest users for a scheduled corporate training.

We invited a small batch; the first several succeeded, then further invitations were blocked by the automated suspicious-activity protection.

Request: please review and lift the suspicious-activity block on B2B invitations for this tenant. I can provide the Tenant ID, the Global Administrator email, the failed invitation request IDs, and any further details via private message.

Thank you for your assistance.

Microsoft Security | Microsoft Entra | Microsoft Entra External ID

1 answer

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  1. AI answer

    2026-06-15T09:49:40.75+00:00

    The block on B2B invitations due to suspicious activity cannot be removed through configuration; it requires direct intervention from Microsoft support.

    Because the tenant is seeing a hard block message (HTTP 403 with “Invitations are blocked for this directory due to suspicious activity. Please contact Microsoft support for help.”), the only viable path is:

    1. Open a support ticket from the affected tenant
      • Sign in to the Azure portal with a Global Administrator account for the blocked tenant.
      • Go to Help + support and create a new support request.
      • Choose the appropriate subscription/tenant and select a problem type related to Microsoft Entra ID / External Identities / B2B collaboration.
      • In the description, include:
        • Exact error text and HTTP status (403 Forbidden).
        • Timeframe when the block started.
        • Approximate number of invitations sent before the block.
        • Sample failed invitation request IDs and correlation IDs from the error responses.
        • Tenant ID and contact details for the Global Administrator.
    2. Work with the Microsoft support / Data Protection team
      • The case will typically be escalated to the internal Data Protection or identity protection team (similar to how tenant lockout and MFA-reset issues are handled in other scenarios in the provided context).
      • That team will review the suspicious-activity flag on the tenant and, if appropriate, remove or relax the block on B2B invitations.
    3. After unblocking
      • Resume sending invitations in smaller, controlled batches to avoid triggering automated protections again.
      • Ensure B2B collaboration settings, cross-tenant access settings, and any allow/block domain lists are configured as intended so that normal policy-based blocks do not interfere with invitations. Relevant configuration areas include:
        • External collaboration settings for B2B in Microsoft Entra ID.
        • Cross-tenant access settings for B2B collaboration.
        • Any allow/block domain lists for invitations.

    The unblock itself cannot be performed by tenant administrators; only Microsoft support can clear this specific suspicious-activity block.

    References:

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