Authenticate chrome extension api

Hi I am developing a chrome extension and I need to authenticate a user based on a Google Plus account. I have implemented with Oauth 2.0. But there are some problems when I execute

chrome.identity.getAuthToken({ 'interactive': true }

No popup for authentication and I checked chrome: // identity-internals / . No token status found for my extension.

I followed all the steps for Chrome authentication and user authentication process

My extension's app id is the same as in Api Credentials (Console.developer.google)

I copied my public key to manifest.json

But there is no hope yet. i manually tried chrome.identity.getAuthToken on advanced background page, i got this error

Unchecked runtime.lastError while running identity.getAuthToken: OAuth2 not granted or revoked.

Copy my code here

manifest.json

{
  "name": "Tinpack",
  "manifest_version": 2,
  "version": "0.1",
  "permissions": [
    "identity",
    "tabs",
    "https://accounts.google.com/*",
    "https://www.googleapis.com/*"
  ],
  "background": {
    "scripts": ["scripts/background.js"]
  },
  "browser_action": {
    "default_icon": {
      "19": "images/icon.png",
      "38": "images/icon.png"
    },
    "default_title": "Tinpack",
    "default_popup": "index.html"
  },
  "oauth2": {
    "client_id": "my client id"
    "scopes": [
      "https://www.googleapis.com/auth/plus.login"
    ]
  },
  "key": "my public key"
  "content_security_policy": "script-src 'self' 'unsafe-eval' https://apis.google.com/; object-src 'self'"
}

      

        
        
        
      

    

Background.js

chrome.identity.getAuthToken({
  'interactive': true
}, function(token) {
  if (chrome.runtime.lastError) {
    alert("Error");
  } else {

    console.log(token);
    alert(token);
  }

});