Try an app preferences reset - Settings then Apps then tap the 3 dots then Reset app preferences, reboot and test but if that fails and this may not be the answer you want to hear but try the below
Performing a system repair using PC Companion will often fix issues - This will factory reset your phone and erase all data so best to backup before you begin
Switch off your phone and unplug from Pc (Hold volume up and power for around 10 seconds)
Start PC Companion and select Support zone then Update my phone/tablet then in Blue Repair my phone/tablet and follow the on screen instructions - When prompted connect your phone still switched off holding volume down or back button - This should start the repair or reformat process
If you are using Windows 8/8.1 or a 64bit operating system then adjust the settings for PC Companion and run in compatibility mode and chose Windows 7 or XP
