errors

<?php
require_once 'dbcon.php';
require_once 'admin/helpers/helper.php';
require_once 'admin/vendors/PHPMailer/phpmailer.php';

$mail = new PHPMailer;

$email = $_POST['email_teacher'];
$token = genRand(12);

if (isset($_POST['submit_email_teacher'])) {

    $send_query = " INSERT INTO teacher (email, token) VALUES ('$email', '$token') ";
    $result = mysqli_query($db, $send_query) OR die(mysqli_error($db));

    $email_query = " SELECT email, token, firstname FROM teacher WHERE email = '$email'  ";
    $result = mysqli_query($db, $email_query) OR die(mysqli_error($db));
    $row = mysqli_fetch_assoc($result);

    try {
        //Server settings
        $mail->SMTPDebug = 1;                               // Enable verbose debug output
        $mail->isSMTP();                                    // Set mailer to use SMTP
        $mail->Host = 'smtp.gmail.com';                     // Specify main and backup SMTP servers
        $mail->SMTPAuth = true;                             // Enable SMTP authentication
        $mail->Username = 'dadangsukatoro@gmail.com';       // SMTP username
        $mail->Password = 'sukatoro456';                    // SMTP password
        $mail->SMTPSecure = 'tls';                          // Enable TLS encryption, `ssl` also accepted
        $mail->Port = 587;                                  // TCP port to connect to

        //Recipients
        $mail->setFrom('rekaulangkali@gmail.com', 'Admin');
        $mail->addAddress($email, $row['firstname']);     // Add a recipient

        //Content
        $mail->isHTML(true);                                  // Set email format to HTML
        $mail->Subject = 'Here is the subject';
        $mail->Body    = $row['token'];
        $mail->AltBody = 'This is the body in plain text for non-HTML mail clients';

        $mail->send();
        echo 'Message has been sent';
    } catch (Exception $e) {
        echo 'Message could not be sent. Mailer Error: ', $mail->ErrorInfo;
    }

}