Plan for external meetings and chat External access policies include controls for both the organization and user levels.
On Windows, navigate to your Taskbar and look for the Microsoft Teams icon.
If you want to Do this: Ensure incoming federated chats and calls arrive in the user's Teams client Configure your users to be TeamsOnly.
Cause These issues can have any of the following causes.
For the ones hosting, ability to assign a co-host to help produce the webinar.
However on some other posts I have seen people state that it was working for them on the desktop client.