Check that another app isn't using your device's camera. If one is, close that app to remove the black screen on FaceTime. Make sure the camera lens isn't blocked.

Some other application using the camera might not have been closed and could be running in the background. Fix Camera being used by another application in Windows 11/10 ...

Make sure all other apps currently using the camera are closed. If another app is actively using the camera on your smartphone, WhatsApp may have trouble accessing the camera.

Camera reserved or blocked by another app? Fix It looks as though another app is already using the camera, Error 0xC00D3704 on Windows 11/10.

If your iPhone's camera is acting strange or otherwise not working, we have some suggestions to help you get it back up and running in no time.

Camera light being used by Camera. Either of these errors means that Flashlight or Camera app cannot be used because another app is using any or both of them.

Another simple thing that can cause the camera on a Mac to appear unresponsive is if you have Screen Time set up and have not given an app permission to use the camera.

Go to the Alexa app, tap the Devices icon at the bottom of the home screen and check to see what your camera's name is in the device list. Then, use it.