预期响应代码 220 但在 laravel 5.6 中得到空响应

Expected response code 220 but got an empty response in laravel 5.6

我正在使用带 laravel 5.6 的 mailgun 发送电子邮件,但它出现 return 错误(预期响应代码 220,但收到空响应)。以下是我所有的文件设置。

.env 文件

MAIL_DRIVER=mailgun
MAIL_HOST=smtp.mailgun.org
MAIL_PORT=587
MAIL_USERNAME = postmaster@domainname 
MAIL_PASSWORD = password
MAILGUN_DOMAIN = domainname 
MAILGUN_SECRET = key
MAIL_ENCRYPTION=tls

mail.php 文件

<?php

return [

     'mailgun' => [
        'domain' => env('MAILGUN_DOMAIN'),
        'secret' => env('MAILGUN_SECRET'),
    ],
    'ses' => [
        'key' => env('SES_KEY'),
        'secret' => env('SES_SECRET'),
        'region' => 'us-east-1',
    ],
    'sparkpost' => [
        'secret' => env('SPARKPOST_SECRET'),
    ],
    'stripe' => [
        'model' => App\User::class,
        'key' => env('STRIPE_KEY'),
        'secret' => env('STRIPE_SECRET'),
    ],
];

services.php 文件

<?php

return [
    'driver' => env('MAIL_DRIVER', 'mailgun'),
    'host' => env('MAIL_HOST', 'smtp.mailgun.org'),
    'port' => env('MAIL_PORT', 587),
    'from' => ['address' => 'aakanskhi.cuminte@gmail.com', 'name' => 'Aakankshi Gupta'],
    'encryption' => env('MAIL_ENCRYPTION', 'tls'),
    'username' => env('postmaster@domain'),
    'password' => env('mailgun password'),
    'sendmail' => '/usr/sbin/sendmail -bs',
    'markdown' => [
        'theme' => 'default',
        'paths' => [
            resource_path('views/vendor/mail'),
        ],
    ],
];
    public function testmail(){
       $user = User::findOrFail(8);
       Mail::send('emails.test',  ['user' => $user], function ($message) {
       $message->from('us@example.com', 'Laravel');
       $message->to('aakankshi.cuminte@gmail.com')->subject('Your Reminder!');
     });
    }

当我 运行 代码时,它给我以下错误消息:

Swift_TransportException 预期的响应代码 220 但得到的是空响应

如何解决此错误消息?

只需 运行 终端上的此代码:

php artisan config:cache

仅对于 Mailgun,您必须在 .env 文件中指定以下字段,仅此而已。

MAIL_DRIVER=mailgun

MAILGUN_DOMAIN=XY.mailgun.org

MAILGUN_SECRET=key-XYZ