OAuth2.0 credential already exists in some project, can't change packageId or keystore

Question

I work in a android gaming company. I am trying to integrate one of our apps with Google Play Game Services. I created the game in Google Play Developer Console and enabled the Game Services API through Google API Console of the app. Both the app and the game are linked to the same Google API Console Project.

Google Play Game Services Developer Console:

Now when I am trying to link the app with the game, I am getting this error when I try to authenticate the app: "Package name and certificate fingerprint combination already exists"

Google Developer API Console:

Error while authorizing the app:

I have read a couple of answers like this one. I can neither change the package name of the app nor I can change our keystore. As our game has a lots of users, changing package id will change its identity. Also, changing keystore means the same (changing company signature, so Google will see us as a new developer now and we will loose all the featuring/marketing).

As the company is pretty big and lots of people, I checked all the Google API Console projects of nearly everyone, but I found no project containing the credential.

The only solution now was to contact Google Support and ask them to provide the project id of the Google API console project which contains the credential. I tried that but I got no response from them.

Please tell if I have gone wrong anywhere or there is some other way to do this.

Answer 1

if i understand you correctly, you have an existing project to which you're adding an Android app, what you need to do is go to Dev console and select the project. Otherwise, click Create project at the top, enter your project name and ID, then click Create.

Note: The name you provide for the project is the name that appears to users in the Google Settings app in the list of Connected apps.

In the left-side navigation, select APIs & auth.

Enable the API you'd like to use by setting the Status to ON.

In the left-side navigation, select Credentials.

Click Create new client ID or Create new key as appropriate for your app.

Complete the form that appears by filling in your Android app details. To get the SHA1 fingerprint for your app, run the following command in a terminal:

keytool -exportcert -alias <keystore_alias> -keystore <keystore_path> -list -v

For example, you're using a debug-key with Eclipse, then the command looks like this:

keytool -exportcert -alias androiddebugkey -keystore ~/.android/debug.keystore -list -v

Then the keystore password is "android". Click Create.