It is one of the most common problems in the Android operating system. Usually, when you open an app, you will see a black screen for a few seconds and then the app will crash with or without an error message. There are a few ways to fix this problem. Most of the time, it might be a temporary loading issue. You just need to press the recent applications menu (usually the first left button) on your phone. Then you close the app that has this issue. Now open the app again. It may work normally. Try a Hard reboot on your Android mobile. Press and hold down the "Home" and "Power" buttons at the same time for up to 10 seconds. Then, release the buttons and hold down the "Power" button until the screen turns on. Now you can try opening the app, it may work fine. If none of the above is working, you can wait till your phone battery drains and it turns off automatically. After that put it to charge, and press the power button. It may work after this. Finally, if you can't fix it with anything, you may need to uninstall the app and reinstall it. Android usually restores all settings after you re-install and log into the app. You can see if that fixes it. Even in some rare cases, the re-install step also doesn't work. If that is your case, try installing older versions of the app. Good luck!