I've set up security pin on my kindle, and once something strange happened. Part of sensor number buttons are not working! To be precise upper and lower rows (1-3 & 0/OK/Cancell) and my 4-digit password has zero and 3 inside, unfortunately.
I tried restarting it and charging and restarting again, but it didn't help.
Hello Zhyrenkov thank you for your message and welcome to the Forum!
I would definitely try CBRetriever suggestion below, a hard restart to the Device. If that does resolve your issue, please contact our Customer Service Team for them to do a reset of the pin so you can use the numbers you have available!
Unfortunately, Amazon has no repair service centers of their own and there are no authorized service centers either. kindles and Fires are not designed to be repaired. However, Customer Service might offer you a small discount on a new one. You can contact them: