Today my wife had a problem where the video would not work while she was on a Zoom call. It was strange as the light for the camera was on but it just showed the camera with a line through it.
To help resolve the issues I followed the steps below.
Open the Windows start menu.
Search for "lenovo" and click Lenovo Vantage.
Click Hardware Settings > Audio/Visual.
Scroll down and switch the Camera Privacy Mode toggle to Off.
Note: If the Camera Privacy Mode keeps changing to On, check if your Lenovo laptop has a physical switch to enable or disable your camera. Make sure it is switched on.