Please go to the menu support and software update to make sure you have the latest update on the television. Once, this is completed or if you're up to date, please try to do a reset of the smart hub.
To reset the smart hub press the Menu key on your remote control. Go to Smart Hub > Smart Hub Reset > Reset Smart Hub. Now, enter your PIN (if you don't remember having set a PIN, it may still be the default PIN, 0000.) You will then receive a message notifying you that the reset is complete.