Laravel Dusk: Facebook\WebDriver\Exception\UnknownErrorException: unknown error: net::ERR_CONNECTION_REFUSED

I faced the same issue and for me what worked was setting the APP_URL parameter in the .env file as:

APP_URL=http://127.0.0.1:8000

As that was the same port on which my php artisan serve would also serve the website i.e.

Laravel development server started: http://127.0.0.1:8000