xbilling - error in frontend

[hackkill CraftHosting]

I have got this error

Code:

array(4) { ["type"]=> int(2) ["message"]=> string(90) "fopen(https://web01.crafthosting.fr/api/xbilling
): failed to open stream: operation failed" ["file"]=> string(57) "/home/crafthosrw/www/manager/classes/xmwsclient.class.php" ["line"]=> int(112) } Problem reading data from https://web01.crafthosting.fr/api/xbilling

But the file api.php have correct permission 777 
And the file config.php in the front-end contain this :

PHP Code:

<?php
  /**
   * API connection settings for xBilling
   * Version : 1.2.0
   * @author Aderemi Adewale (modpluz @ Sentora Forums)
   * Email : goremmy@gmail.com
   * @desc This allows front-end billing package interact with the backend module
  */
                    
  // Config;
     $cfg = array();
     $cfg['api_key'] = '82880*********';
     $cfg['panel_url'] = 'https://web01.crafthosting.fr';
     $cfg['zpx_uid'] = 1;
                    
     if(strpos($cfg['panel_url'], 'http') === false){
         $cfg['panel_url'] = 'https://'.$cfg['panel_url'];
     }                    
?>

Please help me ?
Sorry my english is very bad....