The internal server error is a type of error on the web server that you are trying to access. You may notice internal server error when accessing some pages on a site. The server may be misconfigured that prevents it from responding properly. There are several reasons to display an HTTP 500 internal server error.
Reasons for HTTP 500 Error
The error message indicates that something went wrong in the server. Some times the error may appear due to wrong URLs. First check the website address or URL is correct. If you copied the URL from an email, check you have copied the entire URL or missing something. The three digit status code is used by the webserver to tell the internet browsers that the request is successful or not. If the browser receives the 200 status code, means everything working fine. The error 500 is a collective status code for server errors.
Troubleshoot 500 Error
For website owners and webmasters, first, you must check the Apache (httpd) and PHP error logs of your server. You can see the reasons for the failure from the error logs. First, clear the cache, delete cookies of your browser, and then restart the browser. If the site is still showing the 500 internal server error message, you have no other choices, you have to wait for the website owner to solve the problem. But you can see the pages if the pages are in Google’s cache. To view the cached version of the website just enter the search command cache: followed by the website URL in Google search box (looks like cache:coolefriend.com). You can also use Wayback machine to find the last working page of that website. If the site is well achieved you can see the decades-old version of the website pages.
Error due to the .htaccess file
Check the .htaccess file. If your site using .htaccess file, any syntax error in the .htaccess file can make the HTTP 500 errors. Try to rename or remove (take a backup of the file first) the .htaccess file temporarily and try to reload the page. Sometimes, some error in URL rewriting code in the .htaccess file can lead to an error.
Error due to PHP connection time out
If the PHP scripts use external network connections, their chance to get connection time out (504 gateway timeout). If too many connections are used it may cause an internal server error message.
Error in Scripts
If the site using cgi scripts (ends with .cgi or .pl) then there is a chance to get internal server error due to syntax or coding error. Sometimes a wrong file or directory permission can cause an internal server error. When you install some scripts on your server just checks what files requires which permission to work the script properly. Most scripts have file permission check included in their installation script, so we can see the file and its current permission from the script. If it is not displaying the file permission and noticed some permission must be needed for some specific files from the scripts FAQ or knowledgebase, you can manually change the permission using FTP software. There are three types of file permission rights: read(r), write(w), execute(x). This permission can be assigned for three different user types: the owner of the file, group of users, all others. The file permission rights are specified as abbreviations r, w, and x, or as corresponding numerical values like 755.
Error due to CMS and Script updates
If you are using a CMS for your website. There is a great chance to get a new version of the script or plugin or theme. You must take a backup of the site and database before updating the website or plugin. sometimes the new plugin, theme or child theme may cause some internal error. Find out the theme or plugin that causes the error by disabling it and update it with the latest or with a working version.
Error due to PHP memory limit
A request or a process exceeds a memory limit cannot execute properly resulting in an error. You can increase the PHP memory limit in your script to overcome the issue.
You can contact the administrator of the website through email to tell that the site is not accessible to the world. There is a great chance to get it corrected quickly as the administrator doesn’t have any idea about the web site is not working properly (sometimes may cause after an update of the theme, plugin or the cms module). This will help both of you to solve the issue fast.