Please use the following script. If this doesn't work then it might be some code error from your side.

$mail->SMTPDebug = 0;
$mail->isSMTP();
$mail->Host = 'sg2plcpnl0179.prod.sin2.secureserver.net';
$mail->Port = 465;
$mail->SMTPAuth = true;
$mail->SMTPSecure = true;
Please give it a +1 and also click "Mark As Accepted Solution" if you find it satisfactory. Thanking You With Regards | Harry Parmar