Laravel 5 : deployed on server in public_html give HTTP ERROR 500

I am using laravel 5, I just deployed the code in public_html on the server. When I call the URL it give me the below error

The www.xyz.com page isn’t working

www.xyz.com is currently unable to handle this request.
HTTP ERROR 500

I think this is not a server issue bcoz when I call the phpinfo file http://ift.tt/2jO6Dqp, its work.

I start debugging by echo exit, I found that the problem in bootstrap/app.php at 14 line

$app = new Illuminate\Foundation\Application(
    realpath(__DIR__.'/../')
);

Can anyone suggest me why this happening and how to solve this? Thanks

via Chebli Mohamed