Codeigniter Mail Error 550 5.1.1

Give this config array a try...

Code:

$Config = array(
        'protocol' => 'smtp',
        'smtp_host' => 'xxx.xxx.xxx.my',
        'smtp_port' => 465,
        'smtp_user' => '[email protected]',
        'smtp_pass' => 'xxxxx',
    'smtp_timeout' => 30,
    'newline' => "\r\n",
    'smtp_crypto' => 'ssl',
        'mailtype'=>'html'
        );