A sample FastSpring connection attempt

FastSpring.php

<?php

namespace App;

use GuzzleHttp\Client;

class FastSpring {

    function __construct()
    {
        $this->username = 'WA4N3TEDTB6QHE84I9VYMA'; //config('fastspring.username');
        $this->password = 'o_fXjS-xSDaizvUl-DCCzQ'; //config('fastspring.password');
    }

    public function connect()
    {
        $guzzleClient = new Client();
        $credentials = base64_encode("{$this->username}:{$this->password}");

        // Neither Works (URL) ... I get a 401 Unauthorized Response
        //$response = $guzzleClient->post('https://api.fastspring.com/company/9UIu1yAtQ48', [
        $response = $guzzleClient->post('https://api.fastspring.com', [
            'User-Agent' => ['Guzzle/4.0 curl/7.21.4 PHP/5.5.7'],
            'Authorization' => ['Basic ' . $credentials]
        ]);

        dd($response);
    }
}