herokuでgmailを送信する際のエラーを直したい

herokuを使ってデプロイしたいと考えております。
しかし、下記のエラーメッセージが表示されており、なかなか前に進まない状況です。
ご教授いただけますと幸いです。

Connection could not be established with host smtp.gmail.org

このため、試したことは下記のことです。

1, heroku config set:MAIL_DRIVER: smtp
MAIL_ENCRYPTION: ssl
MAIL_FROM_ADDRESS: メールアドレス
MAIL_FROM_NAME: Tufs-Tours
MAIL_HOST: smtp.gmail.org
MAIL_PASSWORD: パスワード
MAIL_PORT: 465
MAIL_PRETEND: false
MAIL_USERNAME: メールアドレス

2, Gmailの二段階認証たセキュリティ設定の解除
3, config.mailのdriver をsendmailに変更
4, キャッシュをクリアにする
php artisan cache:clear
php artisan config:clear
php artisan route:clear
php artisan view:clear

env
1MAIL_DRIVER=smtp
2MAIL_HOST=smtp.gmail.com
3MAIL_PORT=465
4MAIL_USERNAME=~@gmail.com
5MAIL_PASSWORD=
6MAIL_ENCRYPTION=ssl
7MAIL_FROM_ADDRESS=~@gmail.com
8MAIL_FROM_NAME="Tufs-Tours"
9
10
11
12

<?php

return [

    /*
    |--------------------------------------------------------------------------
    | Mail Driver
    |--------------------------------------------------------------------------
    |
    | Laravel supports both SMTP and PHP's "mail" function as drivers for the
    | sending of e-mail. You may specify which one you're using throughout
    | your application here. By default, Laravel is setup for SMTP mail.
    |
    | Supported: "smtp", "sendmail", "mailgun", "ses",
    |            "postmark", "log", "array"
    |
    */

    'driver' => env('MAIL_DRIVER', 'sendmail'),

    /*
    |--------------------------------------------------------------------------
    | SMTP Host Address
    |--------------------------------------------------------------------------
    |
    | Here you may provide the host address of the SMTP server used by your
    | applications. A default option is provided that is compatible with
    | the Mailgun mail service which will provide reliable deliveries.
    |
    */

    'host' => env('MAIL_HOST', 'smtp.gmail.org'),

    /*
    |--------------------------------------------------------------------------
    | SMTP Host Port
    |--------------------------------------------------------------------------
    |
    | This is the SMTP port used by your application to deliver e-mails to
    | users of the application. Like the host we have set this value to
    | stay compatible with the Mailgun e-mail application by default.
    |
    */

    'port' => env('MAIL_PORT', 465),

    /*
    |--------------------------------------------------------------------------
    | Global "From" Address
    |--------------------------------------------------------------------------
    |
    | You may wish for all e-mails sent by your application to be sent from
    | the same address. Here, you may specify a name and address that is
    | used globally for all e-mails that are sent by your application.
    |
    */

    'from' => [
        'address' => env('MAIL_FROM_ADDRESS', '~@gmail.com'),
        'name' => env('MAIL_FROM_NAME', 'Tufs-Tours'),
    ],

    /*
    |--------------------------------------------------------------------------
    | E-Mail Encryption Protocol
    |--------------------------------------------------------------------------
    |
    | Here you may specify the encryption protocol that should be used when
    | the application send e-mail messages. A sensible default using the
    | transport layer security protocol should provide great security.
    |
    */

    'encryption' => env('MAIL_ENCRYPTION', 'ssl'),

    /*
    |--------------------------------------------------------------------------
    | SMTP Server Username
    |--------------------------------------------------------------------------
    |
    | If your SMTP server requires a username for authentication, you should
    | set it here. This will get used to authenticate with your server on
    | connection. You may also set the "password" value below this one.
    |
    */

    'username' => env('MAIL_USERNAME'),

    'password' => env('MAIL_PASSWORD'),

    /*
    |--------------------------------------------------------------------------
    | Sendmail System Path
    |--------------------------------------------------------------------------
    |
    | When using the "sendmail" driver to send e-mails, we will need to know
    | the path to where Sendmail lives on this server. A default path has
    | been provided here, which will work well on most of your systems.
    |
    */

    'sendmail' => '/usr/sbin/sendmail -bs',

    /*
    |--------------------------------------------------------------------------
    | Markdown Mail Settings
    |--------------------------------------------------------------------------
    |
    | If you are using Markdown based email rendering, you may configure your
    | theme and component paths here, allowing you to customize the design
    | of the emails. Or, you may simply stick with the Laravel defaults!
    |
    */

    'markdown' => [
        'theme' => 'default',

        'paths' => [
            resource_path('views/vendor/mail'),
        ],
    ],

    /*
    |--------------------------------------------------------------------------
    | Log Channel
    |--------------------------------------------------------------------------
    |
    | If you are using the "log" driver, you may specify the logging channel
    | if you prefer to keep mail messages separate from other log entries
    | for simpler reading. Otherwise, the default channel will be used.
    |
    */

    'log_channel' => env('MAIL_LOG_CHANNEL'),

];

Laravel6.0
Mysql
AWSを使用