502 Error

<?php
//Import the PHPMailer class into the global namespace
use PHPMailer\PHPMailer\PHPMailer;
require 'vendor/phpmailer/src/PHPMailer.php';
require 'vendor/phpmailer/src/Exception.php';
require 'vendor/phpmailer/src/SMTP.php';

if ($_SERVER["REQUEST_METHOD"] == "POST") {
  $name = trim(filter_input(INPUT_POST, "name", FILTER_SANITIZE_STRING));
  $email = trim(filter_input(INPUT_POST, "email", FILTER_SANITIZE_EMAIL));
  $details = trim(filter_input(INPUT_POST, "details", FILTER_SANITIZE_SPECIAL_CHARS));

  if ($name == "" || $email == "" || $details == "") {
    echo "Please fill in the required fields: Name, Email, and Details.";
    exit;
  }
  if ($_POST["address"] != "") {
    echo "Bad form input";
    exit;
  }
  if (!PHPMailer::validateAddress($email)) {
    echo "Invalid Email Address";
    exit;
  }

  $email_body = "";
  $email_body .= "Name " . $name . "\n";
  $email_body .= "Email " . $email . "\n";
  $email_body .= "Details " . $details . "\n";

  $mail = new PHPMailer;

  //Tell PHPMailer to use SMTP
  $mail->isSMTP();
  //Enable SMTP debugging
  // 0 = off (for production use)
  // 1 = client messages
  // 2 = client and server messages
  $mail->SMTPDebug = 2;
  //Set the hostname of the mail server
  $mail->Host = 'smtp.gmail.com';
  // use
  // $mail->Host = gethostbyname('smtp.gmail.com');
  // if your network does not support SMTP over IPv6
  //Set the SMTP port number - 587 for authenticated TLS, a.k.a. RFC4409 SMTP submission
  $mail->Port = 587;
  //Set the encryption system to use - ssl (deprecated) or tls
  $mail->SMTPSecure = 'tls';
  //Whether to use SMTP authentication
  $mail->SMTPAuth = true;
  //Username to use for SMTP authentication - use full email address for gmail
  $mail->Username = "xbhlx7@gmail.com";
  //Password to use for SMTP authentication
  $mail->Password = "";


  //It's important not to use the submitter's address as the from address as it's forgery,
  //which will cause your messages to fail SPF checks.
  //Use an address in your own domain as the from address, put the submitter's address in a reply-to
  $mail->setFrom('xbhlx7@gmail.com', $name);
  $mail->addReplyTo($email, $name);
  $mail->addAddress('xbhlx7@gmail.com', 'Joseph Yhu');
  $mail->Subject = 'Library suggestion from ' . $name;
  $mail->Body = $email_body;
  if (!$mail->send()) {
      echo "Mailer Error: " . $mail->ErrorInfo;
      exit;
  }
  header("location:suggest.php?status=thanks");
}

$pageTitle = "Suggest a Media Item";
$section = "suggest";


include("inc/header.php"); ?>

<div class="section page">
  <div class="wrapper">
    <h1>Suggest a Media Item</h1>
    <?php if (isset($_GET["status"]) && $_GET["status"] == "thanks") {
        echo "<p>Thanks for the email! I&rsquo;ll check out your suggestion shortly!</p>";
    } else { ?>
    <p>If you think there is something I&rsquo;m missing, let me know! Complete the form to send me an email.</p>
    <form method="post" action="suggest.php">
      <table>
        <tr>
          <th><label for="name">Name</label></th>
          <td><input type="text" id="name" name="name"></td>
        </tr>
        <tr>
          <th><label for="email">Email</label></th>
          <td><input type="text" id="email" name="email"></td>
        </tr>
        <tr>
          <th><label for="details">Suggest Item Details</label></th>
          <td><textarea name="details" id="details"></textarea></td>
        </tr>
        <tr style="display:none">
          <th><label for="address">Address</label></th>
          <td><input type="text" id="address" name="address">
          <p>Please leave this field blank.</p></td>
        </tr>
      </table>
      <input type="submit" value="Send">
    </form>
    <?php } ?>
  </div>
</div>

<?php include("inc/footer.php"); ?>