PHPMailer 发生致命错误

我正在尝试使用 PHPMailer 通过 gmail SMTP 服务器发送邮件，但出现致命错误，并且找不到任何解决方案

我的 php 文件

<?php
use PHPMailer\PHPMailer\PHPMailer;
use PHPMailer\PHPMailer\Exception;

require "phpmailer/PHPMailer.php";
require "phpmailer/SMTP.php";
require "phpmailer/Exception.php";

$error_msg=null;
$success_msg=null;

if ($_POST) {
    //$name = isset($_POST['name']) ? filter_var($_POST['name'], FILTER_SANITIZE_STRING) : null;
    //$email = isset($_POST['email']) ? filter_var($_POST['email'], FILTER_VALIDATE_EMAIL) : null;
    //$message = htmlspecialchars($_POST['message']);

    $name = $_POST['name'];
    $email = $_POST['email'];
    $message = $_POST['message'];

    if (empty($name) || empty($email) || empty($message)) {
        $error_msg = 'Fill out required entry fields!';
    }

    if (is_null($error_msg)) {

        $mail = new PHPMailer(TRUE);

        $mail->isSMTP();
        $mail->Host = "smtp.gmail.com";
        $mail->SMTPAuth = true;
        $mail->Username = "[email protected] /cdn-cgi/l/email-protection";
        $mail->Password = "";
        $mail->SMTPSecure = "tls";
        $mail->Port = 587;

        $mail->isHTML(true);
        $mail->setFrom($email, $name);
        $mail->addAddress("[email protected] /cdn-cgi/l/email-protection");
        $mail->Subject = "Nowa wiadomość z formularza kontaktowego";
        $mail->Body = $message;

        $mail->send();

        $success_msg = "Message sent.";
    }
}
?>

html表格

<div class="h-100 d-flex justify-content-center align-items-center">
    <div class="row">
        <div class="col-md-12 rounded">
            <?php echo $lang['contact_desc']?>

            <?php if ($error_msg) : ?>
                <div class="alert alert-danger"><?php echo $error_msg; ?></div>
            <?php endif; ?>

            <?php if ($success_msg) : ?>
                <div class="alert alert-success"><?php echo $success_msg; ?></div>
            <?php endif; ?>
            <form id="myform" method="post">
                <label for="name"><?php echo $lang['name']?></label>
                <input type="text" name="name" id="name" placeholder="<?php echo $lang['name']?>" required>

                <label for="email">Email</label>
                <input type="email" name="email" id="email" placeholder="[email protected] /cdn-cgi/l/email-protection" required>

                <label for="message"><?php echo $lang['message']?></label>
                <textarea name="message" id="message" placeholder="<?php echo $lang['msg_content']?>" required></textarea>

                <input type="submit" name="submit" value="<?php echo $lang['submit']?>">
            </form>
        </div>
    </div>
</div>

我得到的错误：

致命错误：未捕获错误：未定义常量 PHPMailer\PHPMailer\FILTER_FLAG_HOST_REQUIRED" 在 C:\xampp\htdocs\phpmailer\PHPMailer.php:3598 堆栈跟踪：#0 C:\xampp\htdocs\phpmailer\PHPMailer.php(3564)： PHPMailer\PHPMailer\PHPMailer::isValidHost('localhost') #1 C:\xampp\htdocs\phpmailer\PHPMailer.php(2304): PHPMailer\PHPMailer\PHPMailer->serverHostname() #2 C:\xampp\htdocs\ phpmailer\PHPMailer.php(1421): PHPMailer\PHPMailer\PHPMailer->createHeader() #3 C:\xampp\htdocs\phpmailer\PHPMailer.php(1316): PHPMailer\PHPMailer\PHPMailer->preSend() #4 C :\xampp\htdocs\scripts\form.php(43): PHPMailer\PHPMailer\PHPMailer->send() #5 C:\xampp\htdocs\contact.php(3): include('C:\xampp\htdocs ...') #6 {main} 抛出在 C:\xampp\htdocs\phpmailer\PHPMailer.php 第 3598 行

有任何想法吗？

The FILTER_FLAG_HOST_REQUIRED 过滤标志 https://www.php.net/manual/en/filter.filters.flags.php在 PHP 7.3 中已弃用，并且 PHPMailer 代码库中不再有任何对它的引用。因此，一个简单的修复方法应该是简单地更新 PHPMailer。如果您使用 Composer，这将是自动的并且非常简单，但您没有，因此您必须下载最新版本并根据自述文件自行安装。