How to solve Magento 500 Server Error?

How to solve Magento 500 Server Error?

500 Internal Server Error. This error has been occure due to inappropriate file permissions.
To solve this error, change the file permission on index.php file hope it will solve this problem.
Go to your cpanel, And click File Manager and then change the file permission of index.php file from 664 to 644.  Also change the permissions of downloader/index.php file to 644 as well otherwise when you will try to access System > Magento Connect >Magento Connect Manager (after magento installation) by logging to magento admin,  you will get 500 Internal Server Error.
And if magento is installed in a folder e.g example.com/magento, in this case you will also change the permission on magento folder to 644