I had this problem because my Android Wear watch is a trusted device and keeps the phone open without needing to enter password. Android Pay apparently requires that a password be entered, and if this hasn't been done prior to checkout it will ask for it. I solved the problem with the following workaround:
Go to Settings/Lock Screen and Security/Secure Lock Settings/secured lock time
Set the lockout time for a relatively short interval such as 3 minutes
Then, prior to entering the shop where you intend to use Android Pay, turn off the Bluetooth on your phone. This will temporarily disable the Smart Lock function, so that as you approach checkout, you will need to log on at the lock screen using your password. Having already logged on with your password, Android Pay will not request your password again at checkout. This has worked for me, and I just need to remember to turn on Bluetooth again when I'm done.
11-05-2017 01:51 PM