If it has happened to you by chance that Clash of Clans it closes, then you must see this to be able to solve it...
There are several reasons why the app of Clash of Clans shuts down unexpectedly, or doesn't load properly.
To rule out minor faults you should:
- Check your internet connection. A poor connection can cause your village to fail to load, black screen, or crash.
- Uninstall and reinstall the app.
- If that just happened after some maintenance, it might be due to some internals of the game that the developers will fix soon so don't rush.