Why won't my phone let me sign in?

[AC Question]

I'm typing in my right pass code, but it keeps saying it's incorrect. I can turn it off and turn it back on, when I slide the screen it will let me on and then kick me back off to the lock screen where it will not let me sign in.

 

[B. Diddy]

Welcome to Android Central! Which phone? You're either entering the wrong code, or some serious glitch has occurred with the phone's firmware.

If it's a Samsung, try using Find My Mobile to remotely change the password.