在Laravel 5.4中使用Mailgun get发送邮件时出现错误代码“401 UNAUTHORIZED` response: Forbidden”

// 在 .env 文件中配置 Mailgun API 密钥
MAILGUN_SECRET=your_mailgun_secret_key

// 在 .env 文件中配置 Mailgun 域名
MAILGUN_DOMAIN=your_mailgun_domain

// 在 config/mail.php 中配置 Mailgun 传输
'mailgun' => [
    'transport' => 'mailgun',
    'secret' => env('MAILGUN_SECRET'),
    'domain' => env('MAILGUN_DOMAIN'),
],

// 发送邮件
use Illuminate\Support\Facades\Mail;

$mail = new \Illuminate\Mail\Message;
$mail->from('sender@example.com', 'Sender Name');
$mail->to('recipient@example.com', 'Recipient Name')->subject('Test Email');
$mail->text('This is a test email.');

Mail::send(['html' => 'emails.test'], ['name' => 'John'], function ($message) use ($mail) {
    $message->from('sender@example.com', 'Sender Name');
    $message->to('recipient@example.com', 'Recipient Name')->subject('Test Email');
});

if (count(Mail::failures()) > 0) {
    // 处理发送失败的情况
    echo "There was one or more failures. They were: " . implode(", ", Mail::failures());
} else {
    echo "Email sent successfully!";
}