Webinar Attendee View Can Not Pin 2 or more

I am hosting the webinar and when I pin two panelists to be viewed on the attendee view there is still only one view and there is nothing happened. When I pin 3 panelists same, only one is on the screen when I check what attendees view. I tried to set up view follow host view I tried gallery view but it's the same.

Does someone know why this happened and how to fix it to have more people at the same time on the spot? 

Thanks.