The Cordova plug-in works perfectly. Until the player logs out via the Leaderboard Log out then the Cordova log in does't work again? the person has to close the game, re-open it, and then it will work again.
The code is still there, but it doesn't work a second time. Works once, signs you in. But if you log out, then the Cordova code to sign you in no longer works, until you close the game and re-open it.