First troubleshooting steps:
REMOVE THE CONFIGURATION
Go to settings, then Configuration.
If it asks for a password, try 1010 or 2275.
Remove the config or tap the trashcan icon at the bottom of the screen.
Reboot the device and try again.
UPDATE THE SOFTWARE
Go to settings
Go to Device Info and then update software.
If it asks for a password, try 1010 or 2275.