Android Google+ example “An internal error occured” error

Today I was going through how to integrate Google + Sign-in button on Android. I was following the tutorial here

After completing all the steps. When i clicked on "Sign in" button I am getting a tooltip with “An internal error occured” error. To fix this problem I did few things and I am not sure which one worked.

1. Make sure to use the same SHA1 fingerprint in Google console when you create a "registered apps"

2. Change

mPlusClient = new PlusClient.Builder(this, this, this)

                .setVisibleActivities("XXXX/AddActivity", "XXXX/BuyActivity")
                .setScopes("PLUS_LOGIN")  // Space separated list of scopes
                .build();

To 

mPlusClient = new PlusClient.Builder(this, this, this)
        .setVisibleActivities("XXXX/AddActivity", "XXXX/BuyActivity")
        .build();