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Lefty's avatar
Lefty
Copper Contributor
Feb 13, 2025

I've set up a Multi Tenant Organization, but I'm not sure if the user contact information is correct

I have two 365 tenants (divisions of the same company) that want to be able to communicate as seamlessly as possible without merging the tenants.
Now from what I could read and see on videos, a Multi Tenant Organization was the way to achieve this.
I've found a number of YouTube videos explaining how to set one up (easy enough it seemed) but none that really showed the effects of this (I think they are pitched at people who probably have experience of B2B collaboration in 365) so I'm not sure exactly what I should expect.

Anyway, I set up the MTO, shared a few users, and also found the "External Access With Trial Tenants" setting (one of the tenants is new, and so still in the trial period). I see the users show in the user lists, with the expected EXT address and a "No" for the "Guest" column, and they appear in each other's "Default Global Address List" in Outlook.. so far, so good

I seem to be able to instigate chats within Teams, which is good.

But if I look at their profiles in outlook or teams, then they always seem to show as offline unless I've got an active chat going on with one, and there is "chat" link for them.

I don't know because so far I haven't found anything that shows, from the user perspective, the result of a correctly set up MTO.

So should I expect the status of a synced user to show their actual connection status to their tenant"? So far they haven't unless I've instigated a chat, and in that case the recognition of the other party being connected only seem to go one way, so only one of the two parties in a cross tenant chat shows as connected in their respective tenants.
And should there be a "Chat" link? (there isn't) 

Note: the above is the profile of a local user who was actually offline not one synchronized in from another tenant. I just used that as it could illustrate the two parts I have questions about.

microsoft 365
microsoft 365 admin center
microsoft teams
  • Lefty's avatar
    Lefty
    Copper Contributor
    Feb 13, 2025

    Hi,
    Thanks for the response, however I'm still having issues.
    I think the first part is working, having done Set-CsTenantFederationConfiguration -SharedSipAddressSpace $true though I'm not quite sure how to test that.
    But as for the second, I still don't have the "chat" link and your instructions don't quite match what I see.

    1. Go to Microsoft Teams Admin Center → External Access
      ok

    2. Ensure "Users can communicate with other Teams users" is enabled
      ???? I see no such option

       

    3. If both tenants allow external access but still have issues, try adding each other's domains manually:
      • Click "Add a domain"

        Where??

      • Enter the other tenant’s domain (tenant2.onmicrosoft.com)
      • Set it to "Allowed"
    4. Restart Teams and Outlook.

    Also, I check Global Address Book policies, neither tenant has one currently.

    As for 
    Ensure Both Tenants Have "People Search" Enabled
    Do you mean "People Insights"?

    regards
    Lefty

  • itadmin-msp's avatar
    itadmin-msp
    Copper Contributor
    Feb 13, 2025

    Hi Lefty, It sounds like you've successfully set up a Microsoft 365 Multi-Tenant Organization (MTO) and enabled user synchronization, but you're facing presence status issues in Outlook/Teams and missing the chat link. Here's what you should expect and how to troubleshoot:

    1️⃣ What You Should Expect in a Correctly Configured MTO

    • Users appear in the Global Address List (GAL) of each tenant ✅ (confirmed in your setup)
    • Users can start Teams chats seamlessly ✅ (confirmed in your setup)
    • Users should appear online/offline accurately across tenants ❌ (this is where you're seeing issues)
    • A "Chat" link should be visible in Outlook & Teams ❌ (missing in your case)

    2️⃣ Why Are Users Showing as Offline Until a Chat Starts?

    Microsoft's MTO does not enable full presence visibility by default across tenants.

    • Teams presence is not fully federated between MTO tenants like it is within a single tenant.
    • A user’s presence updates only after an interaction (e.g., starting a chat) because their status is checked on-demand.
    • This is a known behavior with B2B Direct Connect, which MTO relies on.

    ✅ Workaround: Ensure "B2B Direct Connect" is enabled for Teams presence sync
    Run the following in PowerShell:

    Set-CsTenantFederationConfiguration -SharedSipAddressSpace $true

    Then, restart Teams for both users.

    3️⃣ Why Is the "Chat" Link Missing in Outlook?

    • This can happen if External Access settings are not fully configured.
    • Outlook relies on Teams federation and contact syncing. If presence is not fully synced, Outlook won't show the "Chat" option.

    ✅ Fix: Check External Access in Microsoft Teams Admin Center

    1. Go to Microsoft Teams Admin Center → External Access
    2. Ensure "Users can communicate with other Teams users" is enabled
    3. If both tenants allow external access but still have issues, try adding each other's domains manually:
      • Click "Add a domain"
      • Enter the other tenant’s domain (tenant2.onmicrosoft.com)
      • Set it to "Allowed"
    4. Restart Teams and Outlook.

    4️⃣ Expected Presence Behavior (and Limitations)

    • If a user actively chats, their presence updates temporarily ✅
    • Presence may not persist across sessions ❌ (this is a limitation of MTO)
    • No cross-tenant Outlook presence syncing ❌ (Outlook presence relies on a single Azure AD, which MTO does not merge)

    5️⃣ Additional Fixes (If Issues Persist)

    1. Confirm That Address Book Policies Are Not Preventing Cross-Tenant Visibility
      Run:Get-AddressBookPolicyIf you see separate GALs per tenant, you may need to modify your policy.
    2. Ensure Both Tenants Have "People Search" Enabled
      • Go to Microsoft 365 Admin Center
      • Check if People Search is enabled for both tenants.
    3. Check Azure AD Conditional Access & Security Settings
      • If a tenant has strict policies blocking external users, presence sync may be blocked.

    🚀 Final Answer / Key Takeaways

    • MTO does not provide native real-time presence syncing between tenants by default.
    • Presence status updates only when a chat is started, but disappears afterward.
    • Teams federation settings and B2B Direct Connect should be configured to improve syncing.
    • Outlook may not always show the "Chat" link due to limitations in MTO's cross-tenant presence sync.

    ✅ To Fix These Issues:

    1. Enable Teams External Access & Federation
    2. Run Set-CsTenantFederationConfiguration -SharedSipAddressSpace $true
    3. Manually allow domains in Teams External Access settings
    4. Restart Teams & Outlook for users after changes

    Unfortunately, full real-time presence across tenants is not natively supported in MTO (yet). Let me know if you need more help! 🚀

    • Lefty's avatar
      Lefty
      Copper Contributor
      Feb 21, 2025

      Hi,
      I just noticed I replied to my original post, rather than your response.

      Details are in my post above, but the long and the short of it is that teams chats seem to be working fine (and people's presence status showing correctly), but I still haven't got the "chat" link in outlook.

      I had some trouble following your instructions as what I saw did not match your wording.

      regards

      Lefty

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