I'm actually using Windows 10 Build 17025 (Fall Creators) and I installed True Key on my computer. I use Windows Hello and have a PIN with letters and numbers activated. Unfortunately, True Key is unable to log me in. It's asking me my password to allow the login, I tried my Microsoft's password and my PIN, none of them worked.
Do you know what can I do to fix that?
I suggest you to restart your system once and then try to login using your Microsoft password and check if you are able to login.
Once you are able to login to your system, try to reset the login PIN and check if it works.
1. Click on the Start Menu and select settings.
2. Now select Accounts.
3. Next select the tab Sign-in option.
4. Click on I Forget the PIN and follow the on screen instructions.