Blocking Access to Teams Meeting Chat in External Tenants
A setting in the Teams meeting policy controls whether users can access the meeting chat in meetings hosted by non-trusted external tenants. By default, the setting is On, meaning that users can participate in chat for any meeting they join in any tenant. If you have concerns about this aspect of meetings, turn the setting Off and define trusted tenants. https://office365itpros.com/2023/10/23/block-meeting-chat-untrusted/
