No password input after locking the device from Android Device Manager

I have forgotten my unlock pattern and tried to lock my device with a password on Android Device Manager (ADM). It did lock and a message, "Your device is locked by Android Device Manager" appears, but there's no way of entering a password on that screen.  There's no password field, and just a back click and it's all gone. Pressing​ that lock icon doesn't work, it's not a button, neither sliding up or down, left or right is any good. How to unlock it?