Aweber integration using PHP - php

Question

I am trying to create an auto-login. I don't want my client to login with credentials for this. I am using this library
https://github.com/aweber/public-api-examples/tree/master/php
Created a credentials.ini file like this
clientId = 'xxx'
clientSecret = 'xxx'
accessToken = 'https://auth.aweber.com/oauth2/token'
redirect_uri = 'http://localhost:8080/php-aweber/'
when I try to access the index.php file, It shows an error like this.
//index.php
<?php
require 'vendor/autoload.php';
use GuzzleHttp\Client;
const BASE_URL = 'https://api.aweber.com/1.0/';
// Create a Guzzle client
$client = new GuzzleHttp\Client();
// Load credentials
$credentials = parse_ini_file('credentials.ini');
$accessToken = $credentials['accessToken'];
/**
* Get all of the entries for a collection
*
* #param Client $client HTTP Client used to make a GET request
* #param string $accessToken Access token to pass in as an authorization header
* #param string $url Full URL to make the request
* #return array Every entry in the collection
*/
function getCollection($client, $accessToken, $url) {
$collection = array();
while (isset($url)) {
$request = $client->get($url,
['headers' => ['Authorization' => 'Bearer ' . $accessToken]]
);
$body = $request->getBody();
$page = json_decode($body, true);
$collection = array_merge($page['entries'], $collection);
$url = isset($page['next_collection_link']) ? $page['next_collection_link'] : null;
}
return $collection;
}
// get all of the accounts
$accounts = getCollection($client, $accessToken, BASE_URL . 'accounts');
// get all sharing integration uri's for twitter and facebook
// these are used to create a broadcast that will post to twitter or facebook
// see broadcast example here: https://github.com/aweber/public-api-examples/blob/master/php/create-schedule-broadcast
$integrations = getCollection($client, $accessToken, $accounts[0]['integrations_collection_link']);
echo("Integrations:\n");
foreach ($integrations as $integration) {
if (in_array(strtolower($integration['service_name']), ['twitter', 'facebook'], true)) {
echo "{$integration['service_name']} {$integration['login']} {$integration['self_link']}\n";
}
}
What am I missing or doing wrong?