You should contact specific game support in those matters, because no body here will be able to help you without logs and debug files because there million reasons possible why you got a crash and even if you detect the reason in most reason game developer is only one who can fix it.
But considering you use NVidia powered laptop (GTX 980m) my wild guess it might have to do with Intel GPU in your CPU which is common issue with UE4, you need to make sure that NVidia GPU turn on and always stays when you play UE4 games. Also get latest drivers check power saving options which are usually responsible for switching GPUs .