问PHP Mailer:从gmail向yahoo发送邮件，无法识别的代码

EN

$sentTo = $email;
            $message = "Confirm registration";
            $mail = new PHPMailer;

            //$mail->SMTPDebug = 2;

            $mail->isSMTP();                                      // Set mailer to use SMTP
            $mail->Host = 'smtp.gmail.com';                       // Specify main and backup server
            $mail->SMTPAuth = true;                               // Enable SMTP authentication
            $mail->Username = 'myusername';                      // SMTP username
            $mail->Password = 'password';                       // SMTP password
            $mail->SMTPSecure = 'tls';                            // Enable encryption, 'ssl' also accepted
            $mail->Port = 587;                                    //Set the SMTP port number - 587 for authenticated TLS
            $mail->setFrom('myusername@gmail.com', 'WEBSITE');     //Set who the message is to be sent from
            $mail->addAddress($sentTo);                           // Add a recipient
            $mail->WordWrap = 50;                                 // Set word wrap to 50 characters
            $mail->isHTML(true);                                  // Set email format to HTML

            $mail->Subject = "Travel Smart - Confirm Registration - ";
            $mail->Body    = "<div style='padding: 10px; border-radius: 10px; height: auto; background-image:linear-gradient(to right, rgba(287, 202, 192), rgba(142, 65, 98));opacity:0.8;'><h2 style='font-family:cursive'> WELCOME! </h2> <br> <a href='localhost/log.php?unique_id=$ran_id'><button style='color:white; background:black; pointer: cursor; padding: 10px; border-radius: 20px;'>". $message."</button></a><br></div>";
            $mail->AltBody = $message;

            if(!$mail->send()) {
                echo 'Message could not be sent.';
                echo 'Mailer Error: ' . $mail->ErrorInfo;
                exit;
            }