You screen may appear black during screen sharing due to automatic switching of graphic cards such as the NVIDIA card. To fix this issue (in Windows OS), please follow these steps.
1. Go to the Windows Control Panel.
2. Under
Appearance and Personalisation, select
NVIDIA Control Panel.
3. Under Manage 3D settings, select Program Settings.
4. In the section titled Select a program to customize, click Add.
5. Add zohomeeting.exe from the Zoho/ZohoMeeting directory (located at C:/>Users>YOURUSERNAME>AppData>local>Zoho>ZohoMeeting), then click Add.
6. Select Integrated graphics as the preferred graphics processor.
7. Click Apply, then try sharing your screen again with Zoho Meeting.