External Users Display

Question

Hi All,

We are using Microsoft Teams B2B collaboration to communicate with external users.

In addition, we have configured Teams External Access and added the external domain under:

Teams Admin Center → Users → External Access → Allow specific external domains

For example, we added the domain extdomain.com.

The issue is that when participating in a group chat with users from extdomain.com, some users are displayed as "Unknown" instead of showing their display name and presence information. Chat functionality works correctly, and messages can be sent and received without any errors. However, the external users cannot identify who they are chatting with because the participant appears as "Unknown."

Could anyone advise on the possible causes and how to resolve this issue? Specifically:

• Are there any additional Teams or Entra ID configurations required for presence and identity federation?
• Does the external organization need to enable any settings on their side?
• Are there known limitations when using B2B guest accounts versus Teams federation (External Access)?
• Has anyone encountered a scenario where chat works successfully, but display names and presence information are not resolved and show as "Unknown"?

Any guidance would be greatly appreciated.

Answer 1

Hello Glenn Maxwell,

Thank you for your detailed explanation, it really helps in understanding your setup and what you are observing.

Before going further, may I kindly ask how long you have had the External Access configuration in place? In some cases, this behavior can be related to provisioning or synchronization delays, especially shortly after enabling or updating the configuration.

Regarding your questions:

1. Are there any additional Teams or Entra ID configurations required for presence and identity federation?

There are no additional specific configurations required beyond enabling External Access and allowing the relevant domains. Once these are in place, the communication layer is already functioning as expected. 

2. Does the external organization need to enable any settings on their side?

External Access works as a two-way configuration, so both organizations (tenants) need to have External Access enabled and allow each other’s domains.

You can refer to the following Microsoft documentation for more details: IT Admins - Manage external meetings and chat with people and organizations using Microsoft identiti…

3. Are there known limitations when using B2B guest accounts versus Teams federation (External Access)?

Yes, there are known differences between these two approaches. External Access (federation) is more limited in terms of identity resolution and presence sharing, while B2B guest accounts provide a more complete experience.

For a detailed comparison, you may refer to: Use guest access and external access to collaborate with people outside your organization - Microso…

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If after a few days the issue still persists and users continue to appear as “Unknown”, I would recommend opening a support ticket with Microsoft Support. In some cases, backend assistance may be required, and the support team can help trigger a manual synchronization between Teams and Microsoft Entra ID if needed.

For your reference: Get support - Microsoft 365 admin | Microsoft Learn

Thank you again for your patience and for sharing such a detailed case. Please feel free to keep me updated, I’ll be happy to assist further where possible.

Warm regards,

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Answer 2

In Teams and Entra ID, this behavior is expected in some external/federated scenarios and is usually not caused by a misconfiguration in B2B or External Access.

When external (federated) users join meetings or calls, Teams admin tools query Entra ID for user properties such as displayName. Because external users are not present in the local Entra directory in the same way as internal or B2B guest users, their identity information is not always available to be resolved and is therefore shown as Unknown. This is by design for external/federated identities.

Key points from the documented behavior:

• For external users, the Teams admin experience uses Microsoft Graph to query the local Entra tenant for user properties.
• External/federated users are not available for those queries, so their name is displayed as Unknown in the UI where that lookup is performed.
• Chat and meeting functionality can still work correctly even when the UI shows Unknown for name/presence.

Implications for the questions raised:

• Additional Teams or Entra ID configuration for “presence and identity federation”: The documented behavior indicates that the Unknown display for external users is expected and not something that can be fully corrected by additional configuration when the user is purely external/federated and not represented as a guest object in the local Entra tenant.
• Settings required on the external organization side: The Unknown behavior stems from how the local tenant resolves user properties, not from a missing setting on the external tenant. As long as external access/federation is allowed on both sides, chat will work even if the UI cannot resolve the external user’s display name.
• B2B guest vs. Teams federation (External Access):
  • Guest access (B2B collaboration) creates a guest user object in the local Entra directory (UserType = Guest). That object can have displayName and other attributes that Teams can read directly.
  • External access (federation) does not create such a local user object; the user remains in their home tenant. In these cases, certain admin views and identity lookups can show Unknown because there is no local Entra object to query.
• Scenario where chat works but names/presence show as Unknown: This is explicitly documented for external users in call/meeting analytics and is by design. The same underlying limitation (no local Entra object to query) explains why chat participants from an external domain may appear as Unknown in some views even though chat itself works.

To improve identity resolution, organizations that need richer identity and presence for specific external users typically:

• Use B2B guest access for those users (so a guest object with a display name exists in the local Entra tenant), instead of relying solely on external access/federation.

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References:

• External users appear as Unknown in meeting details
• Use guest access and external access to collaborate with people outside your organization
• IT Admins - Manage external meetings and chat with people and organizations using Microsoft identities
• Configure external collaboration settings for B2B in Microsoft Entra External ID
• Authentication and Conditional Access for External ID