PhPMailer: Errore

require("class.phpmailer.php");

$mail = new PHPMailer();

$mail->IsSMTP(true);                             
$mail->Host     = "out.alice.it"; 
$mail->SMTPAuth = true;     
$mail->Username = "xxxx";  
$mail->Password = "xxxxxx"; 

$mail->From     = "info@xxx.it";
$mail->FromName = "Mailer";
$mail->AddAddress("xxx@xxx.com","xxxx"); 
$mail->AddAddress("xxx@xx.it");
$mail->AddAddress("xxx@xx.it");         
$mail->AddReplyTo("info@xxx.it","Information");

$mail->WordWrap = 50;                          
$mail->IsHTML(false);                              

$mail->Subject  =  "xxxxx";
$mail->Body     =  "xxxx";
$mail->AltBody  =  "xxxxx";

if(!$mail->Send())
{
   echo "Messaggio non inviato.</br>";
   echo "Mailer Error: " . $mail->ErrorInfo;
   exit;
}

echo "Messaggio inviato";