我最近接手了一个Laravel项目，我正在设置开发环境，其中包括配置项目使用MySQL数据库。我已经成功地配置了大部分的环境设置;然而，我遇到了一个问题与电子邮件确认功能.尽管对.env文件进行了更改以指向正确的邮件服务器，但应用程序似乎仍在尝试使用上一个项目中的邮件服务器设置。这将导致以下错误消息：

Connection could not be established with host previous.group.mailserver.com :stream_socket_client(): php_network_getaddresses: getaddrinfo failed: The specified host is unknown.

我还更改了Mail：send的所有用途，以使用我的开发电子邮件：

Mail::send($view, $mail_data, function ($message) use ($mail_data) {
            $message->to($mail_data['receiver_mail'], $mail_data['receiver_name'] . " " . $mail_data['receiver_surname'])->bcc('X', 'X')->subject('Confirmation Mail');
        });

mail.php

<?php
return [
    'driver' => env('MAIL_DRIVER', 'smtp'),
    'host' => env('MAIL_HOST', 'smtp.mailgun.org'),
    'port' => env('MAIL_PORT', 587),
    'from' => [
        'address' => '[email protected]',
        'name' => 'development email',
    ],

    'encryption' => env('MAIL_ENCRYPTION', 'tls'),
    'username' => env('MAIL_USERNAME'),
    'password' => env('MAIL_PASSWORD'),
    'sendmail' => '/usr/sbin/sendmail -bs',
];

.env

APP_NAME=X
APP_ENV=local
APP_KEY=X
APP_DEBUG=true
APP_LOG_LEVEL=debug
APP_URL=http:http://localhost

UNIQUE_SERVER_URL=X/

BROADCAST_DRIVER=log
CACHE_DRIVER=file
SESSION_DRIVER=file
QUEUE_DRIVER=sync

REDIS_HOST=127.0.0.1
REDIS_PASSWORD=null
REDIS_PORT=6379

PUSHER_APP_ID=
PUSHER_APP_KEY=
PUSHER_APP_SECRET=

MAIL_DRIVER=smtp
MAIL_HOST=smtp.gmail.com
MAIL_PORT=587
MAIL_USERNAME=X
MAIL_PASSWORD=X
MAIL_ENCRYPTION=ssl

DATABASE=X
DATABASE_USERNAME=X
DATABASE_PASSWORD=X

composer.json

{
    "name": "laravel/laravel",
    "description": "The Laravel Framework.",
    "keywords": ["framework", "laravel"],
    "license": "MIT",
    "type": "project",
    "require": {
        "php": ">=7.0.0",
        "barryvdh/laravel-cors": "^0.11.2",
        "fideloper/proxy": "~3.3",
        "laravel/framework": "5.5.*",
        "laravel/tinker": "~1.0"
    },
    "require-dev": {
        "filp/whoops": "~2.0",
        "fzaninotto/faker": "~1.4",
        "mockery/mockery": "0.9.*",
        "phpunit/phpunit": "~6.0"
    },
    "autoload": {
        "classmap": [
            "database/seeds",
            "database/factories"
        ],
        "psr-4": {
            "ThekRe\\": "app/"
        }
    },
    "autoload-dev": {
        "psr-4": {
            "Tests\\": "tests/"
        }
    },
    "extra": {
        "laravel": {
            "dont-discover": [
            ]
        }
    },
    "scripts": {
        "post-root-package-install": [
            "@php -r \"file_exists('.env') || copy('.env.example', '.env');\""
        ],
        "post-create-project-cmd": [
            "@php artisan key:generate"
        ],
        "post-autoload-dump": [
            "Illuminate\\Foundation\\ComposerScripts::postAutoloadDump",
            "@php artisan package:discover"
        ]
    },
    "config": {
        "preferred-install": "dist",
        "sort-packages": true,
        "optimize-autoloader": true,
        "allow-plugins": {
            "kylekatarnls/update-helper": true
        }
    }
}

我也按照类似问题的指示做了，但没有成功：
Connection could not be established with host mailtrap.io [php_network_getaddresses: getaddrinfo failed: No such host is known. #0]