“500 Internal Server Error”

In most occasions, file and folder permissions cause this “500 Internal Server Error” issue on Magento. To solve this issue, just change the folder permissions as below:

1. Change the following folder permissions to 755

– app/etc
– var
– media

2. And change the following file’s permission to 644

– index.php – root level index.php file on Magento installation
– downloader/index.php

If have set the wrong permissions on the downloader/index.php file, you can’t access the Magento connect manager(System -> Magento Connect -> Magento Connect Manager)

However, the above fixes only apply to the Magento versions prior to 2.x.