Rear camera not working-How do I fix it?

[ed kiptugulit]

Rear camera not working. What is the reason

 

[B. Diddy]

Welcome to Android Central! There are a lot of possible reasons, but we would need more details. Does it give you an error message when you try to open it? Does it open, but only show you a blank image? Does nothing happen at all when you try to open it? How about the front-facing camera?

See if the problem persists in Safe Mode: https://support.t-mobile.com/docs/DOC-14146. If it does, then either the camera hardware has failed, or the firmware is corrupt. For a 4 year old phone, I'd bet on a hardware failure.