Cannot start a meeting - blank screen no controls

I have been hosting meetings regularly, the last one was last Thursday, but yesterday, upon launching, instead of the regular screen with controls, I got a blank screen with only my ID and no controls (see screen capture). Attendees joined (in another screen) I could see them and hear them but I could not join my own meeting. I closed the meeting for everyone, created another meeting, same thing. I had to cancel the meeting. I have been testing creating meetings and launching, and still the same blank screen with no controls. I have updated to the latest Zoom Client 5.13.10 - nothing changes.

I submitted a ticket to Zoom support yesterday, no reply. And I have another meeting planned for tomorrow Thursday. Any ideas, solutions? Many thanks.