try new mailboxcheck

zimbraAddressAvailable.php

@@ -9,7 +9,7 @@ define("CLIENTAREA", true);
 require_once(__DIR__ . '/../../../init.php');
 require_once("api/Zm/Auth.php");
 require_once("api/Zm/Account.php");
-use WHMCS\Database\Capsule;
+use Illuminate\Database\Capsule\Manager as Capsule;
 
 $whmcs = App::self();
 $productID = $_GET['pid'];