the numbers and letters on pin keypad hidden by white boxes

[AC Question]

my phone is locked with a pin. when i turn my phone on a keypad come up so that i can input the pin. Today my keypad numbers and letters have been replaced by white boxes. the numbers and letters are hidden

 

[B. Diddy]

Welcome to Android Central! That glitch happens from time to time, usually on Samsung devices. You should still be able to tap the correct key combination. Then reboot the phone. You might also try wiping the cache partition if the reboot doesn't help. If you don't know how, tell us which device you have.