Participants unable to see real-time typing on my Whiteboard

I created a whiteboard a few months ago that I have been using weekly in my meeting. Until today, participants have been able to see what I am typing in realtime and see when my cursor highlights words or sentences. Today however, they could only see the new information after I stopped typing and the whiteboard finished saving. 

I have checked that everyone has collaborator status, and the only thing that I have done differently was that I had shared the whiteboard with them and set them as editors. 

I tried changing their collaborator status, unsharing the whiteboard, closing the whiteboard and re-opening it. Nothing works.