Steam executable game error

hello guys, i recently developed a game for a friend of mine on c3, i exported it in nw version, when he uploaded the game on the steam store normally, but the game doesn't work on some computers, the game window disappears and the game on steam is running, does anyone have a definitive solution for this error I don't know what else to do since the error is not in the executable but in steam

Ashley could you clarify me please

You need to collect information to work out what the problem is. You need to find out what hardware and OS versions the users that are having issues are using and what additional software they are running, and you need to look for patterns. That will help you narrow down the cause of the issue. It could be thousands of different things. Could be corrupted installations, gfx card/driver issues, interference from anti-virus etc.

No-one can just tell you what it is without data to examine.