Laravel-Excel xlsx download request not working

I'm using the Maatwebsite/Laravel-Excel(version 2.1) library in Laravel to download an xls file.

class ControllerApi extends Controller {

     private $excel;

     public function __construct(Excel $excel) {
         $this->excel = $excel;
     }

     public function getXlsFile(Request $request) {
           $this->excel->create("Report2016", function($excel) {

            // Set the title
            $excel->setTitle('My awesome report 2016');

            // Chain the setters
            $excel->setCreator('Me')->setCompany('Our Code World');

            $excel->setDescription('A demonstration to change the file properties');

            $data = [12,"Hey",123,4234,5632435,"Nope",345,345,345,345];

            $excel->sheet('Sheet 1', function ($sheet) use ($data) {
                $sheet->setOrientation('landscape');
                $sheet->fromArray($data, NULL, 'A3');
            });

        })->export("xlsx");
     }
}

Even though the response header seems to be okay, the browser don't download the file.

Anyone knows what I'm doing wrong?

Thanks in advance.

via Chebli Mohamed