Q:

InappBilling Error- authentication is required. you need to sign into your google account

I am trying to make a demo of inappbilling. I followed this tutorial for studying this. 
Lemme tell the steps I followed for doing this task

I used the below mentioned code
package com.ohn.inappbilling;

import android.content.Intent;
import android.os.Bundle;
import android.support.v7.app.ActionBarActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;

import com.hello.inappbilling.util.IabHelper;
import com.hello.inappbilling.util.IabResult;
import com.hello.inappbilling.util.Inventory;
import com.hello.inappbilling.util.Purchase;
import com.ohn.inappbilling.R;

public class MainActivity extends ActionBarActivity {

private static final String TAG = "com.hello.inappbilling";
static final String ITEM_SKU = "com.buttonclick";
IabHelper mHelper;
private Button clickButton;
private Button buyButton;

@Override
protected void onCreate(Bundle savedInstanceState) {
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_main);
    buyButton = (Button) findViewById(R.id.buyButton);
    clickButton = (Button) findViewById(R.id.clickButton);
    clickButton.setEnabled(false);
    String base64EncodedPublicKey = "******";

    mHelper = new IabHelper(this, base64EncodedPublicKey);

    mHelper.startSetup(new IabHelper.OnIabSetupFinishedListener() {
        public void onIabSetupFinished(IabResult result) {
            if (!result.isSuccess()) {
                Log.d(TAG, "In-app Billing setup failed: " + result);
            } else {
                Log.d(TAG, "In-app Billing is set up OK");
            }
        }
    });
    //throw new RuntimeException();
}

public void buttonClicked(View view) {
    clickButton.setEnabled(false);
    buyButton.setEnabled(true);
}

public void buyClick(View view) {
     mHelper.launchPurchaseFlow(this, ITEM_SKU, 10001,   
           mPurchaseFinishedListener, "mypurchasetoken");
}

@Override
protected void onActivityResult(int requestCode, int resultCode, 
     Intent data) 
{
      if (!mHelper.handleActivityResult(requestCode, 
              resultCode, data)) {     
        super.onActivityResult(requestCode, resultCode, data);
      }
}

IabHelper.OnIabPurchaseFinishedListener mPurchaseFinishedListener 
= new IabHelper.OnIabPurchaseFinishedListener() {
public void onIabPurchaseFinished(IabResult result, 
                Purchase purchase) 
{
   if (result.isFailure()) {
      // Handle error
      return;
 }      
 else if (purchase.getSku().equals(ITEM_SKU)) {
     consumeItem();
    buyButton.setEnabled(false);
}

}

};

public void consumeItem() {
    mHelper.queryInventoryAsync(mReceivedInventoryListener);
}

IabHelper.QueryInventoryFinishedListener mReceivedInventoryListener 
   = new IabHelper.QueryInventoryFinishedListener() {
       public void onQueryInventoryFinished(IabResult result,
          Inventory inventory) {

          if (result.isFailure()) {
          // Handle failure
          } else {
                 mHelper.consumeAsync(inventory.getPurchase(ITEM_SKU), 
            mConsumeFinishedListener);
          }
    }
};

IabHelper.OnConsumeFinishedListener mConsumeFinishedListener =
new IabHelper.OnConsumeFinishedListener() {
 public void onConsumeFinished(Purchase purchase, 
       IabResult result) {

if (result.isSuccess()) {                
      clickButton.setEnabled(true);
} else {
       // handle error
}
}
};

@Override
public void onDestroy() {
    super.onDestroy();
    if (mHelper != null) mHelper.dispose();
    mHelper = null;
}

}

I created apk using File-Export-AndroidProject and uploaded this in alphatesting.
I added users(Google group) in Manage list of testers in alpha testing.
I added the product in In-app Product and give id to it com.buttonclick
In settings in Gmail accounts with testing access I added Gmail id's here also. None of the id is developer id.

Can anyone tell solution for this problem. I have tried all the solutions available on StackoverFlow.

A:

I found solution for this problem.
I published this apk on playstore and then I downloaded apk from playstore and ran that and It worked fine 
I think the reason behind this problem is 
The google account that I was using for testing may be it was not the main account.

