Answer to "How do I get the cameras to work again?"try doing a hard restart . please update the phone software , please close all other background app and rsetart the system . for more follow Guide - steps fix to Phone Camera in phone and try to see if this helps to fix the camera
Answer to "Why isn't my Camera working?"hold the power key and wait for 1 min than let the power key go . now try updating the phone software to fix if it is a bug . close all background programs and for more please follow Guide -Fix Phone Camera Step By Step and i hope this will help you to fix the camera .