warning: mail() [function mail]: SMTP server response: 550.5.7.1 <email@gmail.com>... Relaying denied. IP name possibly forged [191...] in line 100

mail($destinatario,$asunto,$body);

$sql = "select EMAIL1_CLI from planilla_imbra_cobranza";

                $rpt = mysqli_query($sub_db,$sql)or die(mysqli_error());
                //$asunto = 'Aviso de Deuda';

                $mail             = new PHPMailer(); // defaults to using php "mail()"
                $body             = "Este es un mensaje automatico...";


                $mail->From       = "no-responder@xx.cl";
                $mail->FromName   = "Francisco Acevedo Diaz";



                $mail->AddAddress('francisco@gmail.com','Clientes'); //deb poner variable que traiga mail y nombre del cliente
                $mail->SetFrom('cobranza@xx.cl', 'Depto. Cobranza');



                $asunto = $mail->Subject = 'Aviso de deuda en oriental Motors';


                $mail->AltBody    = "To view the message, please use an HTML compatible email viewer!";
                $mail->MsgHTML($body);



                $mail->IsSMTP();
                $mail->Host = "mail.xx.cl";


                // optional
                // used only when SMTP requires authentication
                $mail->SMTPAuth = true;
                $mail->Username = 'xx';
                $mail->Password = 'xx';


                while ($des = mysqli_fetch_array($rpt)) {
                    $destinatario = $des["EMAIL1_CLI"];
                    printf ($destinatario);

                    //$mail->AddAddress = $des['EMAIL1_CLI'];
                    //$mail->AddAddress("facevedo@xx.cl");
                    mail($destinatario,$asunto,$body);

                }

                    if(!$mail->Send()) {
                      echo "Mailer Error: " . $mail->ErrorInfo;
                      exit;
                    } else {
                      echo "Message sent!";
                    }
                }