Can't access to back-office

[kokou z]

Hello, someone who can help me?

I can't have access to back office of my website

it show me this error  

Oops! An Error Occurred

The server returned a "500 Internal Server Error".

Something is broken. Please let us know what you were doing when this error occurred. We will fix it as soon as possible. Sorry for any inconvenience caused.

[Juan Rios1]

Turn on debug mode to see more information. 

Assuming you have prestashop V.1.6

Navigate into : config\defines.inc.php

look for :

/* Debug only */
if (!defined('_PS_MODE_DEV_')) {
define('_PS_MODE_DEV_', false);
}

replace false with true to receive an error.

Or you could try looking at your server error logs.