External users are unable to continue Microsoft Teams meeting chat after the meeting ends (cross-tenant federation scenario)

Question

Issue Description

We have two separate Microsoft 365 tenants.

Users from both tenants are standard users in their respective tenants (not guests).

They are able to:

Join Microsoft Teams meetings across tenants

Chat during the meeting

However, after the meeting ends:

External users are unable to continue the chat

The meeting chat either becomes inactive or does not allow further communication

Expected Behavior

Users from both tenants should be able to:

Join meetings using their own tenant accounts

Continue using the same meeting chat after the meeting ends, similar to internal users

Current Behavior

Chat works during the meeting

• After the meeting ends → chat is not usable for external users

This behavior is inconsistent (works in some tenant combinations, fails in others)

Configurations Verified

Microsoft Teams Admin Center

External Access = Enabled

Allow all external domains = Enabled

No blocked domains configured

Microsoft Entra ID

Cross-tenant access settings = Default (Allow)

No inbound or outbound restrictions

No tenant-specific blocking policies

User Behavior

• Users are signed into Teams (not anonymous/browser users)
• Using the desktop client

Observation

• In some scenarios, chat persists after the meeting
• In other scenarios, chat does not persist

This occurs despite identical configurations.

Questions to Microsoft

Is persistent chat after meetings for federated (external) users officially supported behavior?

What conditions are required for a meeting chat to transition into a persistent chat thread for external users?

Is this behavior controlled by:

Meeting policies?

  Federation settings?
  
     Backend service logic?
     
     Why does the same configuration work between some tenants but not others?
     
     Is there any way to enforce or guarantee chat persistence after meetings for external users?
     
     Are there any known limitations or recent changes affecting this behavior?
     

Final Request

We need confirmation on:

Whether this is expected behavior or a limitation

• If there is any supported configuration or workaround to ensure external users can continue chatting after meetings consistently

Answer 1

Hi @Avinash Dhanukonda,

Thank you for reaching out to the Microsoft Q&A forum.

Based on the scenario you described, this behavior is generally expected in Microsoft Teams and is not usually caused by a tenant misconfiguration.

With External Access /federation, users from different Microsoft 365 tenants can typically:

• Join meetings
• Use the meeting chat during the meeting

However, continuing to use that same meeting chat after the meeting ends is not guaranteed for federated (non-guest) users.

According to Microsoft documentation, people outside your organization may only have temporary access to meeting chat, and in some cases they won’t retain access after the meeting ends. Microsoft also notes that external users may not have access to meeting chat history the same way internal users do.

This is why the behavior can appear inconsistent between different tenant combinations, even when the visible settings look the same. In this case, the limitation is more related to how Teams handles cross-tenant meeting chat on the service side, rather than something that can be fully controlled through External Access, Cross-tenant access settings, or meeting policies.

So to answer your main question directly: there is currently no supported setting that guarantees persistent post-meeting chat for federated external users in all scenarios.

If your organization needs external participants to reliably continue using the same chat after meetings, the more supported option would be to use Guest access (B2B) instead of federation, since guest users are handled more like participants within the host tenant.

You can review the official Microsoft articles below for reference:

• Access meeting chat in Microsoft Teams - Microsoft Support
• IT Admins - Manage external meetings and chat with people and organizations using Microsoft identit…
• Use guest access and external access to collaborate with people outside your organization - Microso…

If you need confirmation for a specific tenant-to-tenant scenario, I would recommend opening a support ticket with Microsoft so the Teams backend behavior can be reviewed in more detail. Hope this information will help.

Answer 2

Persistent post-meeting chat for external (federated, cross-tenant) users is limited and depends on how those users join and how the meeting/chat is scoped. Based on the provided information, the behavior described aligns with current limitations rather than a fully guaranteed, supported “always persistent” experience for all external users.

Key points from documented behavior

1. Anonymous and some external accounts have no chat outside the meeting
   • For meetings with people outside the org, people “joining a meeting anonymously or from other accounts outside your org won’t have access to the meeting chat outside of the meeting.”
   • This means that if the external participant is treated as anonymous or as an “outside account” for that meeting context, they can chat only while the meeting is running and lose access once it ends.
   • Reference behavior: external users can be in the meeting and chat during it, but cannot continue once the meeting ends.
2. Meeting chat availability can be restricted by meeting policy
   • Meeting chat behavior is controlled by CsTeamsMeetingPolicy via -MeetingChatEnabledType:
     • EnabledExceptAnonymous – chat allowed for everyone except anonymous users.
     • Disabled – chat disabled.
     • EnabledInMeetingOnlyForAll – chat only during the meeting; no pre- or post-meeting chat.
     • EnabledInMeetingOnlyForAllExceptAnonymous – chat only during the meeting and anonymous users cannot see or write in chat.
   • If the organizer’s policy is set to EnabledInMeetingOnlyForAll or EnabledInMeetingOnlyForAllExceptAnonymous, then all participants (including external/federated users) will see exactly what is described: chat works during the meeting but is not usable before or after.
3. External access and compliance behavior
   • External access (federation) has specific compliance and retention behaviors:
     • External chats are subject to the policies of the org where the chat is created, and “the shortest retention policy applies.”
     • External chats can become read-only if all participants in the org where the chat was created are removed from that org.
   • For external access chats (federated), some compliance features (DLP, information barriers) do not apply, which indicates that external/federated chat is handled differently from internal or B2B guest chat.
4. External meeting and chat with Microsoft identities
   • External meetings and chat with Microsoft identities are governed by external access and compliance rules. The documentation focuses on how external access interacts with eDiscovery, retention, and DLP, but does not provide a guarantee that all external meeting chats will persist post-meeting in the same way as internal-only meetings.
5. ACS/anonymous interop behavior (for comparison)
   • When a Communication Services (ACS) user joins a Teams meeting anonymously, they “can send and receive messages with other users in the meeting” but “don’t have access to chat messages that were sent before they joined the meeting” and “can’t send or receive messages after the meeting ends.”
   • This shows a clearly documented pattern for non-tenant/anonymous participants: chat is strictly in-meeting only.

Answers to the specific questions

1. Is persistent chat after meetings for federated (external) users officially supported behavior?
   • Documentation confirms that:
     • Anonymous and “other accounts outside your org” do not have access to meeting chat outside the meeting.
     • Meeting chat can be configured to be “in-meeting only” for all participants via policy.
   • There is no explicit guarantee in the provided documentation that cross-tenant federated users will always have persistent post-meeting chat identical to internal users. Where external users are treated similarly to anonymous/“outside” accounts, in-meeting-only behavior is expected.
2. What conditions are required for a meeting chat to be persistent for external users? From the documented controls, the following are required for any user (internal or external) to have post-meeting chat:
   • The organizer’s meeting policy must not be set to EnabledInMeetingOnlyForAll or EnabledInMeetingOnlyForAllExceptAnonymous.
   • The user must not be treated as anonymous or as an “outside account” that is restricted to in-meeting chat only.
   • External access and cross-tenant settings must allow the user to participate as a federated identity rather than anonymous.
   If any of the above are not met, the result is in-meeting-only chat.
3. Is this behavior controlled by meeting policies, federation settings, or backend logic?
   • Meeting policies: Yes. Set-CsTeamsMeetingPolicy -MeetingChatEnabledType directly controls whether chat is available only during the meeting or also before/after.
   • Federation/external access: Yes, in the sense that how the external user is classified (federated vs anonymous/“outside account”) determines whether they can have chat outside the meeting at all.
   • Backend service logic: Yes, but not configurable by admins beyond the documented policy and external access settings. The service decides whether a given participant is treated as anonymous, external, guest, or internal based on identity and cross-tenant configuration.
4. Why does the same configuration work between some tenants but not others?
   • The documentation provided does not enumerate all backend conditions, but the following documented factors can differ per tenant pair:
     • The organizer’s CsTeamsMeetingPolicy (especially MeetingChatEnabledType). Different organizers/tenants may have different policies, leading to in-meeting-only chat in some cases and persistent chat in others.
     • How external access and cross-tenant trust are configured and how the service classifies the external user (as federated vs effectively “outside/anonymous”).
     • Retention and compliance policies that can affect how long external chats remain available.
5. Is there any way to enforce or guarantee chat persistence after meetings for external users? Within the documented controls, the only enforceable levers are:
   • Ensure the organizer’s Teams meeting policy has MeetingChatEnabledType set to allow pre/post meeting chat, for example not using EnabledInMeetingOnlyForAll or EnabledInMeetingOnlyForAllExceptAnonymous. For example:

          Set-CsTeamsMeetingPolicy -Identity <policy name> -MeetingChatEnabledType EnabledExceptAnonymous
     

   • Ensure external users are not joining anonymously and that external access is configured so they are treated as federated users rather than anonymous/“outside” accounts.
   Beyond these, there is no documented, admin-exposed setting that guarantees that all cross-tenant federated users will always have persistent post-meeting chat identical to internal users.
6. Are there any known limitations or recent changes affecting this behavior?
   • The provided documentation explicitly calls out limitations for:
     • Anonymous/“outside” participants: no chat outside the meeting.
     • ACS/anonymous interop: chat only during the meeting.
   • It also documents that some compliance features (DLP, information barriers) do not apply to external access chats and that external chats follow the shortest retention policy, which can limit persistence.

Summary

• The described behavior (external users can chat during the meeting but not after) is consistent with documented limitations for anonymous/“outside” participants and with meeting policies that restrict chat to “in-meeting only.”
• Persistent post-meeting chat for external/federated users is not guaranteed by documentation; it depends on:
  • The organizer’s CsTeamsMeetingPolicy (MeetingChatEnabledType).
  • How the external user is classified (federated vs anonymous/“outside”).
  • Retention/compliance policies in the organizer’s tenant.
• To maximize the chance of persistent chat:
  • Use a meeting policy such as EnabledExceptAnonymous for organizers.
  • Ensure external users join as signed-in, federated users (not anonymous) and that external access is allowed.

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References:

• Access meeting chat in Microsoft Teams
• Manage chat in Microsoft Teams meetings
• IT Admins - Manage external meetings and chat with people and organizations using Microsoft identities
• Quickstart: Join your chat app to a Teams meeting (platform-windows)
• Add or invite people outside your org to a chat in Microsoft Teams