Not found page in Lumen after install [duplicate]

One Way:

In /public/index.php change

$app->run();

$app->run($app['request']);

This also works too (faster):

$app->run($app->make('request'));

php laravel routes lumen

When you aren't using php artisan serve, what are you using? If you're using vanilla php -S you need to also specify the public directory like so:

php -S localhost:8000 -t public/

You would need to do this inside of your lumen directory.