laravel 5.1白屏错误;

I am working on a project and i just completed some tasks; eventually we need to deploy it on ftp for test. I am stuck right there when it shows only the blank page; .htaccess file is working, index.php is also reachable; it works up to line 50 of index.php:

$kernel = $app->make(Illuminate\Contracts\Http\Kernel::class);
// upto this every thing is fine but

After this line echo command is not working means error is right there

$response = $kernel->handle(
    $request = Illuminate\Http\Request::capture()
 );
$response->send();

$kernel->terminate($request, $response);

I set appropriate permission to folders storage and bootstrap; and php version is 5.5.9. How can i shoot this problem; it took really long time what's the problem with it