1) Try closing all of the apps that are running in the background and then re-open your app.
2) If that does not work please try powering off your device and then restarting it.
3) If all else fails you may need to try deleting the app and reinstalling it from the App Store.
Please note that by deleting your app you are also deleting any bookmarks you have saved and these can not be recovered.
If you continue to experience problems, please email us at firstname.lastname@example.org.