If this does not resolve your issue, do one of the following:
Reboot your device. Switch off the device, and remove the battery. After about a minute, replace the battery, and switch on the device.
Restore the original factory settings.
Update your device software.
If your issue remains unsolved, contact Nokia for repair options. Go to www.nokia.com/repair. Before sending your device for repair, always back up the data in your device.