Can't see participants anymore when screen sharing on dual monitors

[ChrisE2]

I have been using Zoom very successfully for online teaching for the past 2 years and am a great fan. I am starting to teach a new course tomorrow. When i did a trial run today, I found that something had changed: When I started screen-sharing from a second camera (a document camera I use to do math on), the participants' videos suddenly disappeared and did not return after I stopped screen-sharing. All my settings and hardware are exactly the same as for the courses i taught before. Can anyone please advise me how to get my participants' videos back? I had no problem with this before, and have not done anything differently.  Any help will be much appreciated, thank you.

[tnichols]

I am having the same issue. 

[MGSR]

Welcome to the Zoom Community @ChrisE2! We sincerely appreciate your contribution to bringing up this issue and sharing it with the community. Such participation is highly encouraged, as it allows other users to provide solutions and assistance. 

You may need to re-enable the dual monitor set-up. 

To enable the dual monitors feature for your own use:

1. Sign in to the Zoom Client.
2. In the top-right corner of the Zoom Client, click your profile picture then click Settings.
3. Click the General tab.
4. Select the Use dual monitors check box.
   
   Note: On the macOS version of the desktop client, dual monitor mode can be enabled with the Command(⌘)+Shift+D keyboard shortcut.

You may read more in this article.
This article on sharing multiple screens simultaneously may also help.

Thank you, and have a fantastic day