Share your experience!
let's go by steps, are you saying that it works when you clear the app data but then it stops working?
Follow Phy's advice and if that doesn't work then I recommend running a software repair on the handset.
To run a software repair you firstly need to download PC Companion or Bridge for Mac if you have a Mac computer.
The process will delete all user data however you can do a back up beforehand:
To back up your phone using PC Companion
1. Go to Support to install PC Companion on a Windows computer.
2. When installed, start PC Companion on the computer.
3. Connect your phone to the computer using a USB cable.
4. Click Start under Backup & Restore.
5. Follow the on-screen instructions.
Running the software repair
1. Install and open PC Companion then select Support Zone.
2. Phone Software Update.
3. Start.
4. Repair Phone
5. Continue
6. Accept data removal
7. Next
8. Wait for prepare
9. Select Phone
10. Follow the connection steps
Hope this helps 