Cannot sign into Google Play Services when using Unity and Play Games Plugin for Unity

I am unable to connect to Google Play with GPG. I "Build and Run" from Unity, Android phone is connected through USB to the PC. Here's the log error:

 PlayGamesServices[SignInAuthenticator]: **** APP NOT CORRECTLY CONFIGURED TO USE GOOGLE PLAY GAME SERVICES
 PlayGamesServices[SignInAuthenticator]: **** DEVELOPER_ERROR
 PlayGamesServices[SignInAuthenticator]: **** This is usually caused by one of these reasons:
 PlayGamesServices[SignInAuthenticator]: **** (1) Your package name and certificate fingerprint do not match
 PlayGamesServices[SignInAuthenticator]: ****     the client ID you registered in Developer Console.
 PlayGamesServices[SignInAuthenticator]: **** (2) Your App ID was incorrectly entered.
 PlayGamesServices[SignInAuthenticator]: **** (3) Your game settings have not been published and you are 
 PlayGamesServices[SignInAuthenticator]: ****     trying to log in with an account that is not listed as
 PlayGamesServices[SignInAuthenticator]: ****     a test account.
 PlayGamesServices[SignInAuthenticator]: ****
 PlayGamesServices[SignInAuthenticator]: **** To help you debug, here is the information about this app
 PlayGamesServices[SignInAuthenticator]: **** Package name         : com.___.___
 PlayGamesServices[SignInAuthenticator]: **** Cert SHA1 fingerprint: 8C:C7:...:BD:D6
 PlayGamesServices[SignInAuthenticator]: **** App ID from manifest : 86...64
 PlayGamesServices[SignInAuthenticator]: ****
 PlayGamesServices[SignInAuthenticator]: **** Check that the above information matches your setup in 
 PlayGamesServices[SignInAuthenticator]: **** Developer Console. Also, check that you're logging in with the
 PlayGamesServices[SignInAuthenticator]: **** right account (it should be listed in the Testers section if
 PlayGamesServices[SignInAuthenticator]: **** your project is not yet published).
 PlayGamesServices[SignInAuthenticator]: ****
 PlayGamesServices[SignInAuthenticator]: **** For more information, refer to the troubleshooting guide:
 PlayGamesServices[SignInAuthenticator]: ****   http://developers.google.com/games/services/android/troubleshooting
 PlayGamesServices[SignInAuthenticator]: ****

Here are the screenshots that show everything is a match. I also added the correct email addresses to the "Testers" area (the one on my phone I use to login to Google Play). Sorry for the heavy redaction!!!

Google Cloud OAuth
Play Game Services Config
In-use SHA-1 Certificate
Unity Android Setup

I have built time and again, restarted the Android, I did everything I could possibly think of. Still does not work. I get the above log error every single time.

From the log error, (1) and (2) can be checked off from those screenshots. (3) I'm not really sure what they mean by "game settings have not been published", but I filled everything in in the Console, so I think that's set. Also, I added my Google Play e-mail as tester, so that should be well taken care of.

Well, I'm not sure what else to do. Can... anyone please help? Thanks! I would really appreciate it as I am fully stuck!