If you forgot lock screen password on Kindle Fire Devices. Then follow the steps:
1.On the lock screen, swipe from the right side edge of the screen.
2.Enter an incorrect password or PIN five times.
3.After that, you will be prompted to reset your device or wait 30 seconds to try again.
4.Reset to reset your device to factory defaults.
If you are still having some issues contact at Kindle Customer Service passcode Assistance team at +1-877-930-1494. Visit us at http://kindletechhelp.com/