When it's turned off, your device may not recognize that there's a camera installed, or it may cause your camera to show an image of a camera with a slash through it.
Solution 2: Check the connection speed Aim for the right internet speeds for a successful video chat.
If it is just a minor app issue, then resetting WhatsApp will be enough to make things work perfectly again.
If you are using mobile data, you will need at least 3G.
If you hear an audio echo or feedback, there are three possible reasons why.
Note: The in-box UVC driver may not support all the features of your camera.
You can check if you are on the newest version by simply opening the Google Play Store and searching for WhatsApp.
I've found that pro mode drastically darkens all photos.