Microsoft Graph: AllowMeetingChat set to limited does not allow attendees to chat

Hi Maria Pequeno Camarero

In Microsoft Graph, allowMeetingChat controls the meeting chat mode. Microsoft documents this property as part of the onlineMeetingconfiguration, while the participants property separately represents the organizer and attendees associated with the meeting. The documentation does not state that allowMeetingChat = limited grants chat access only to users explicitly included in the attendeescollection.

For Teams meetings, limited corresponds to making meeting chat available during the meeting rather than before or after it. However, actual chat availability can also be affected by Teams meeting policies and, importantly, by how the participant is identified when joining. Microsoft notes that meeting chat policies can control whether participants are allowed to read and send messages and can specifically restrict anonymous meeting participants from using chat,

Therefore, I would pay particular attention to the participants who join directly through joinWebUrl. If Teams cannot establish a trusted/authenticated identity for a participant, that participant may be treated as anonymous/unverified. Microsoft describes participants whose identities cannot be verified as anonymous, whereas guests and users from trusted organizations can be treated as verified external participants.

This could also help explain why an attendee invited through People > Share invite during the meeting behaves differently. Rather than assuming that adding the attendee to the Graph attendees collection is itself what enables chat, I would compare the identity under which the attendee joins in both scenarios.

As a test, you could:

• Add one affected user explicitly to participants.attendees when creating the online meeting and test again.
• Have the same user join through the original joinWebUrl while signed in to Teams with their work or school account.
• Check whether Teams displays the participant as External, Guest, or Unverified.
• Review the organizer's Teams meeting policy > Meeting chat setting, particularly whether anonymous participants are excluded from chat. Microsoft specifically documents that the Teams admin meeting-chat policy can prevent anonymous participants from using meeting chat.

If the explicitly listed attendee can use chat while the same user joining otherwise cannot, collecting the participant identity/status and the Graph request/response would be useful for narrowing down whether this is related to participant resolution in the Graph-created standalone meeting.

For reference:

onlineMeeting resource type - Microsoft Graph

Manage chat in Microsoft Teams meetings

Plan for meetings with external participants

I hope this information helps. If you have any further questions or can share the participant type shown in Teams for the affected users, please feel free to ask.