In order to fix the issue, I suggest you try updating its firmware. Connect the device to Internet, press the Set/OK button and then 2 times the Down option. When the Advanced Settings appears, press Set/OK and then Down once. After that, wait the Upgrade Now! message to appear and press the Set/OK twice. Follow the on-screen instructions and after your phone is restarting, press Set/OK button and then UP until you see Setting Options. Press Set/OK, UP and Set/OK again after the Restore Factory option appears. Once again press Set/OK and wait several seconds. If it still doesn't work, try reconfiguring it using the official user guide.