Fatal error: Class 'PHPMailer' not found in C:AppServwwwSolicitudesBEconexion.php on line 58

require_once('PHPMailer-master/PHPMailerAutoload.php');
                //require_once('/PHPMailer/class.phpmailer.php');

                $mail = new PHPMailer;

                $mail->IsSMTP();
                //$mail->SMTPDebug = 2;
                $mail->SMTPAuth = false;
                $mail->SMTPSecure = "tls";
                $mail->Host = "correo.domain.org.mx";
                $mail->Port = 25;
                $mail->Username = "julio.castor@domain.mx";
                $mail->Password = "pass";
                $mail->SetFrom('correo@domain.com', 'Julio Castor');
                $mail->Subject = $asunto;