Register the CatchAllOptionsRequestsProvider service provider in bootstrap/app.php which will check the incoming request and response successfully if it is an OPTIONS request.
Add the CorsMiddleware to the $app->middleware([ array in bootstrap/app.php which will attach the following CORS headers to all responses:
- allow all headers
- allow requests from all origins
- allow all the headers which were provided in the request



@rgehan solutions works perfectly adding a Middleware. Im Working Lumen 5.4 in vhost (custom domain) and consuming via Angular4 (locahost)
===
UPDATE > @rgehan your solution doesn't work on anonymous function - download method