500 internal server error at back end – Joomla

First you have change folder permission to 775 for the following folders:

cache, logs, tmp & administrator/cache

then go to: configuration.php

find code:

$log_path="XXXXXXXXXXXXX";
$tmp_path="XXXXXXXXXXXXX";

and change code into:

$log_path="./logs";
$tmp_path="./tmp";

problem solved 🙂