There are a number of responses about the camera so let's talk about post production. If you're shooting in RAW you then have a great deal of latitude to safety adjust exposure in post production. You can also tweak shadow and highlights and fine tun...
It's unlikely that the camera is not functioning correctly. If the camera is set to Auto Focus but the subject is too close for the lens to focus on the camera will not shoot. Or if you're aiming at a blank subject like a wall then the camera can't f...