Can you try typing you password again but don't hit "return" on the keyboard. Instead hit anywhere outside to close the keyboard. The passwords not displayed but if you press "go" it should proceed to the next screen.
If it still doesn't work, you can reset the password by pressing "forgot your password?" on the bottom of the screen. Afterward the game will send you with a new password which you can enter.
Remember the password is case-sensitive so lowercase and uppercase needs to be exact.
This is a known issue and it is being addressed. We appreciate your patience and cooperation in the meantime.