User unable to redeem cross-tenant Teams channel invite

Question

Hello,

We enabled cross-tenant and setup the external org in our Entra Admin console while also allowing access across the board.
However it looks like our users are unable to join the external teams channel of the other tenant. Not sure if this is due to MFA trust not being a part of our subscription of if we missed a step somewhere.

Happy to provide more info where needed.

Answer 1

Hi,

Thank you for posting your query on Microsoft Q&A.

The issue where users are unable to redeem cross-tenant Teams channel invites despite having enabled cross-tenant access typically relates to configuration nuances in Microsoft Entra cross-tenant access policies and external identity settings.

Steps to Resolve Cross-Tenant Teams Channel Invite Issues

1. Cross-Tenant Access Settings:

• Confirm both tenants (your tenant and the external one) have proper cross-tenant access policies configured:
  • Go to Microsoft Entra admin center > External Identities > Cross-tenant access settings.
    • Ensure inbound and outbound settings allow collaboration between the two tenants (either for all users or for specified users/groups).
      • Policies should allow all required authentication and session controls.

2. MFA and Authentication Trust:

• If MFA trust is required for your subscription or external tenant policies, verify that the external tenant supports the necessary MFA authentication methods.
• An absence or misconfiguration of MFA trust can cause access failures to shared Teams resources.

3. User Invitation Redemption:

• Verify that invited external users have properly redeemed their invitations in Teams or via email link.
• Check they use the email associated with their Azure AD account.
• Errors like AADSTS50107 often indicate misconfigured federation or guest sign-in policies.

4. Permissions and Channel Visibility:

• Make sure the external user has been granted membership or guest access to the team/channel.
• Verify Teams settings do not restrict guest access or external sharing.

5. Propagation Delay:

• Remember changes to cross-tenant access can take up to six hours to propagate globally.

6. Logs and Error Messages:

• Encourage users to report error messages, if any, as they often provide clues to misconfiguration or policies blocking access.

Additional References

• Set up cross-tenant access policies
• Use guest access and external access to collaborate with people outside your organization - Microsoft Teams | Microsoft Learn
• Microsoft Entra External Identities FAQ

Please click "Accept as Answer" if this resolves your issue. This will help others with the same problem find a solution.