My code is executing the code in the "if" statement that checks for blank strings, even if the strings aren't blank!

<?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';


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_SPECIAL_CHARS));

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

  echo "<pre>";
  $email_body = "";
  $email_body .= "Name " . $name . "\n";
  $email_body .= "Email " . $email . "\n";
  $email_body .= "Details " . $details;
  echo $email_body;
  echo "</pre>";

  // Todo: Send Email
  header("location:suggest.php?status=thanks");
}
$pageTitle = "Suggest a Media Item";
$section = null;


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 your e-mail! I&rsaquo;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="email" id="email" name="email"></td>
        </tr>
        <tr>
          <th><label for="details">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"></td>
          <p>Please leave this field blank.</p>
        </tr>      
       </table>
      <input type="submit" value="Send">
    </form>
    <?php } ?>
  </div>
</div>