Please perform the following steps to resolve the mentioned issue:
1- Settings > apps > tap on 3 dots (Upper right corner) > reset app preferences.
2- Force stop the particular app (Settings > Apps > camera app > Force stop).
3- Clear the RAM memory of device (Settings > Device care > Memory > Clean Now).
For further assistance, register your concern in Samsung members app(Open Samsung members app>click on “+“icon>send feedback>Error report/ Ask Questions).
Team Samsung Members
I am facing same issue, got the phone delivered today & camera is not working. It says "Camera Failed".
Amazon is not ready for refund , they are going to provide replacement. Hope the replacement work. But lost the trust on Samsung, in-fact i dont want to use M30S as i lost trust. Not Sure how a new phone can have this problem.