persistent menu error

[ibrahem-kamal]

hi i am getting this error even though i ran

php artisan fb:get-start WELCOME_MESSAGE

and the output is success , i am following your demo but i dont know what i am doing wrong , here is the code i have

menu.php

Menu::locale('default', function () {
    Menu::postback('Test Button', 'WELCOME_MESSAGE');
    Menu::webUrl('WebUrl', 'https://github.com/CasperLaiTW/laravel-fb-messenger');
});

fb-messenger.php

return [
    'debug' => env('APP_DEBUG', false),
    'verify_token' => env('MESSENGER_VERIFY_TOKEN'),
    'app_token' => env('MESSENGER_APP_TOKEN'),
    'app_secret' => env('MESSENGER_APP_SECRET'),
    'auto_typing' => true,
    'handlers' => [
        ShowProductMenuHandler::class
    ],
    'custom_url' => '/chatbot',
    'postbacks' => [
        WelcomePostback::class,
        BuyProductPostback::class,
        ConfirmedProductPostback::class,
        CanceledProductPostback::class,
    ],
    'home_url' => [
        'url' => env('MESSENGER_HOME_URL'),
        'webview_share_button' => 'show',
        'in_test' => true,
    ],
];

(#100) You must set a Get Started button if you also wish to use persistent menu.