No matter what I do, I cannot speak with external orgs on Teams. They can't even find me

Basit Mohammad 0 Reputation points
2026-08-27T16:22:51.2333333+00:00

This is really frustrating, I have enabled all settings for external collaboration but I cant even find the external orgs on Teams I keep getting hit with this message: We can't set up the conversation because your organizations are not set up to talk to each other."

Everything I could've has been enabled but it's not working. The external org says it works for them for other orgs.

Screenshot 2026-08-27 at 12.20.44 PM.png

Microsoft Teams | Microsoft Teams for business | Chats | Other
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  1. AI answer

    2026-08-27T16:23:07.57+00:00

    This error usually means external access federation is still blocked somewhere between the two organizations, even if most settings look enabled.

    Check these items in order:

    1. In the Teams admin center, go to Users > External access.
      • Verify Teams and Skype for Business users in external organizations is set to Allow all external domains, or that the other organization’s domain is explicitly allowed.
      • By default, Teams allows all external domains, but if an allow list is configured, every other domain is blocked.
      • If a block list is configured, confirm the external domain isn’t on it.
    2. Confirm the other organization has also enabled external access and allows your domain.
      • External access is two-way. Both organizations must trust each other.
      • If the other tenant doesn’t trust your domain, users in that tenant won’t be able to chat with users in your organization.
    3. Check whether trial-only tenant federation is blocked.
      • Teams blocks communication with trial-only tenants by default unless changed with PowerShell.
      • The relevant setting is -ExternalAccessWithTrialTenants in Set-CsTenantFederationConfiguration.
    4. If specific domains are being blocked, check subdomains.
      • Blocking contoso.com doesn’t block marketing.contoso.com unless -BlockAllSubdomains $True is configured.
    5. Run the federation diagnostic in the Microsoft 365 admin center.
      • Enter the affected user and the federated tenant domain, then run the test.
      • The diagnostic returns the next steps for settings or policy issues that are preventing communication.
    6. If the external users still can’t find the account after the settings are confirmed, this can require backend investigation.
      • A similar Microsoft Q&A case for external calling/search issues recommends opening a support request in the Microsoft 365 admin center under Support > Help & Support.

    Also note:

    • External chat and meetings use external access, not guest access.
    • External participants don’t get access to teams or channels through external access; they remain signed in to their own organization.
    • By default, users in one organization can communicate with all other Microsoft 365 domains only if the other organization also enabled external access.
    AI-generated content may be incorrect. Read our transparency notes for more information.

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  2. BabybooHN 2,955 Reputation points Independent Advisor
    2026-08-27T16:49:25.87+00:00

    Dear @Basit Mohammad

    I fully understand how frustrating it is when external communication fails despite having enabled the external collaboration settings in the Microsoft Teams admin center.

    The error message "We can't set up the conversation because your organizations are not set up to talk to each other" indicates that while your Teams external access settings are properly configured, a restriction in Microsoft Entra ID (formerly Azure AD) Cross-tenant access settings or Domain Blocklists is blocking federation at the identity layer.

    Because external federation requires mutual configuration, here is how you can locate and fix the issue step-by-step:
    Step 1: Check Microsoft Entra ID Cross-Tenant Access Settings

    Teams external access relies on Microsoft Entra ID B2B collaboration settings. If cross-tenant access restricts inbound or outbound communications, Teams will display this exact error.

    • Sign in to the Microsoft Admin Center > Microsoft Entra admin center as a Global Administrator or Security Administrator.
    • Navigate to External Identities > Cross-tenant access settings.
    • Under Organizational settings, check if the external domain's tenant ID or domain is listed specifically.
    • If it is listed, click Inbound access and Outbound access for that organization to ensure that B2B direct connect and B2B collaboration are set to Allow.
    • Under Default settings, select Edit inbound defaults and Edit outbound defaults to ensure that general access settings are not set to Block for external users. User's image

    Step 2: Verify Blocked Domains in Teams Admin Center

    Even with "All external organizations" allowed in custom mode, explicit domain blocks override open permissions.

    • Sign in to the Microsoft Admin Center > Microsoft Teams admin center.
    • Navigate to External > External access.
    • Under Choose which unmanaged Teams users your users can communicate with, ensure Block specific domains does not list the external organization's domain. User's image

    Step 3: Verify the External Organization's Tenant Configuration

    Even if the external organization states it works with other companies, their policy may explicitly block your specific tenant ID/domain, or they may restrict external communication to specific allowed domains only.

    Have an admin from the external organization verify their Microsoft Entra ID Cross-tenant access settings (Outbound/Inbound settings) to ensure your domain is not explicitly blocked or omitted from their allowed tenant list.

    For further reference on configuring these settings, please consult the official Microsoft documentation on Configuring cross-tenant access settings for B2B direct connect.

    Please try these steps and let me know if updating the Entra ID settings resolves the issue.

    If the answer is helpful, please click "Yes" and kindly upvote it. If you have extra questions about this answer, please click "Comment".   

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