To fix an HTTP 500 internal server error, clear the browser's cache and cookies, restart the browser and try to reload the Web page. Optionally, contact the website's administrators to report the problem. If the error is on your own site, check for any incorrect permissions in the site's configuration, reconfigure timeout rules and check whether the website's .htaccess file is correct.
An HTTP 500 internal server error is often accompanied by directions to check the server's error log for more information that provides precise information on the problem. For problems associated with directory or file permissions, set permissions on files and folders to 0775 and try again. PHP scripts that connect to external resources can lead to an HTTP 500 internal server error on timeout of external scripts. To fix this, edit the script's error handling rules to deal with timeout errors more efficiently.
Misconfiguration in a site's .htaccess file may lead to an HTTP 500 internal server error. Check for syntax errors, and reload the page. Optionally, remove or rename the file, and reload the page to rule out .htaccess file errors. A good rule of thumb is to use a plain text editor for all scripts and save them in pure ASCII text format to avoid introducing special characters that may cause scripts to fail.