Could you please provide a little more information so I can better understand where the problem is occurring? When you say “keycode,” are you referring to your Windows PIN/password, a BitLocker recovery key, or another security code?
What exactly is displayed on the screen where you are unable to enter it? If possible, please share a photo or screenshot, making sure not to include any passwords, PINs, recovery keys, or other personal information.
Does the keyboard not respond at all when you press keys, or does it allow you to type but reject the code? Is this the built-in keyboard of a laptop, or an external USB/Bluetooth keyboard?
Can you use the mouse/touchpad normally on that screen? Was the computer working normally before this happened, and did the issue start after a Windows update, restart, or other change?