Experiencing an “Internal Server Error” in WordPress can be frustrating, but it’s a common issue with several potential solutions. This guide will walk you through the most effective methods to diagnose and resolve this error, ensuring your website is up and running smoothly again.
Understanding the Internal Server Error
An Internal Server Error (also known as a 500 error) is a generic server error message indicating something has gone wrong on the server side, but the server cannot be more specific about what the exact problem is. There could be many things causing this specific error, and we’ll explore them one by one.
Does Clearing the Browser Cache Help?
No. Some articles claim that clearing the browser cache should fix this issue, but it’s a server issue. In some rare cases, this could be caused by a cookie, but that’s less than 1%. If you really want to test this, open a private window or tab in your browser and navigate to the same page that was showing the 500 internal server error. We are 99.99% sure that the same error message will show up. It’s a server error, after all.
Inspect the Web Server’s Log Files
The very first thing you should do is inspect the web server’s log files for that specific site. Scroll to the very end of the file to see if there’s an error. This can give you a hint about what went wrong.
You will most likely see an error message like this.
Invalid command 'XYZ', perhaps misspelled or defined by a module not included in the server configuration, referer: https://s-q3l58tabj3czl.eu1.wpsandbox.org/wp-admin/
A Corrupted .htaccess File
The .htaccess file is used by the Apache web server to define some rules that may override server defaults. Examples include mod_rewrite rules, redirects, granting or denying access to certain files, increasing the PHP memory limits, etc. The .htaccess file is not accessible directly from the web and is only accessible by file managers within your control panel.
How .htaccess File Errors Occur
By entering a random character, invalid command, or invalid syntax in the .htaccess file, this is likely to cause an internal server error. The server needs to tell you that the configuration is wrong. Here are examples of correct and incorrect entries:
- Correct:
SetEnv SOME_VAR 1 - Incorrect:
SetEnv SOME_VAR=1 - Incorrect:
SetEnv SOME_VAR:1
Note: it turned out that the Apache env module doesn’t crash and creates the env variable without a value.
KEY [SPACE] VALUE
Another possible reason might be that the .htaccess file is trying to use a given module’s features, but that module is not installed or activated yet.
Example of a Proper .htaccess Configuration
in this case we check if mod_rewrite module is available and then use its features. This reduces the changes of the site crasing when we migrate the site to another server or WordPress hosting provider.
<ifModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteCond %{QUERY_STRING} /?author [NC]
RewriteRule .* - [F]
RewriteCond %{QUERY_STRING} g= [NC]
RewriteRule ^(.*)$ - [F,L]
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</ifModule>
Find the Root Cause of the Issue
The very first thing that you should do is inspect the web server’s log files for that specific site. Scroll to the very end of the log file to see what’s the error message. Then you can paste it into ChatGPT or Gemini to ask them what might be causing this.
You could also contact your WordPress Hosting Support to have it resolved.
Steps to Fix the Corrupted .htaccess File
- Access Your WordPress Root Directory: Use an FTP client or your hosting provider’s file manager to navigate to the root directory of your WordPress installation. That’s the folder where wp-config.php resides.
- Rename the .htaccess file: Rename the existing .htaccess file to something like .htaccess_old to disable it.
- Try Accessing Your Website: Check if your website is accessible and if the error is still there. If it is, the issue was with the .htaccess file.
- Generate a New .htaccess File: Log into your WordPress dashboard, go to WP-Admin > Settings > Permalinks, and click Save Changes. This will generate a new .htaccess file with default rules.
- Check Server Logs: If the error persists, check your server logs for any additional errors.