One possibly way to solve this problem, It's look if your camera is working wrong or it's not taking photos. you can solve this problem updating your camera drivers. in case that this hadn't solved the error, you can try to open your camera and force it to work only by letting it try to take photos or videos. This last worked to me because of my computer camera is a little broken and it's old. if the error persists, maybe the program (the programming language you are using) doesn't have permission to use your computer's camera, you just must go to camera privacy settings from your operating system and activate the permissions of your camera for your program. I hope this helps to anyone who is reading this answer :).