It would help if you could specify how/where/when the app is crashing. A crash could be caused by almost anything, and saying it crashes doesn't really give any information.
Does your app use isolated storage settings? If you try to access a setting that doesn't exist you might get a crash. When testing locally you would likely have these settings already created from previous testing of the app.
Try creating a new Microsoft account and log into your device to run the app. You might find that it crashes only for new users, which is a sign of incorrect isolated storage use.
Does your app rely on external data? Your connection could be failing and/or your app could be getting incorrect data from an external source.
You really need to find out what line(s) of code make the app crash and then investigate from there.
I'm a self-taught noob amateur. Please take this into account when responding to my posts or when taking advice from me.