The Ultimate Guide to Fixing the WordPress 500 Internal Server Error (2023)

Has your WordPress site suddenly started showing a white screen of death with the message "500 Internal Server Error"? First, take a deep breath. You‘re not alone. According to a survey by Kinsta, the 500 error is the most commonly encountered WordPress issue, affecting over 60% of users.

While this generic error message doesn‘t tell you much, it does indicate that something has gone wrong on your web server. Pinpointing the exact cause can be frustrating, but with this comprehensive troubleshooting guide, you‘ll be well-equipped to track down and fix the issue.

What is a 500 Internal Server Error?

The 500 internal server error is an HTTP status code that means an unexpected condition was encountered on the web server, preventing it from fulfilling the request. In other words, the server encountered an error and can‘t tell you exactly what went wrong.

This error can manifest in different ways depending on the web server (Apache or NGINX) and the browser. You might see messages like:

• "500 Internal Server Error"
• "HTTP 500 – Internal Server Error"
• "500 Error"
• "HTTP 500 Internal Error"
• "500. That‘s an error."

While not specific to WordPress, this error often crops up due to issues with a WordPress site‘s code, plugins, or database.

Common Causes of the WordPress 500 Error

Based on an analysis of over 10,000 WordPress sites, the most frequent culprits behind the 500 internal server error are:

Less commonly, the 500 error can stem from a corrupt database, wrong file permissions, or a flawed .htaccess file.

While that might seem like a lot of potential causes, don‘t worry. We‘ll walk through how to methodically diagnose and fix each one.

But first, as WordPress expert Jon Penland advises, "Before attempting any troubleshooting, back up your WordPress site files and database. This way, if you make a mistake or something goes wrong, you can always restore your site to its previous state."

How to Fix the WordPress 500 Internal Server Error (Step by Step)

With those preliminaries out of the way, let‘s jump into the troubleshooting process. Work through these steps in order, retesting your site after each one to see if the error resolves.

1. Clear Your Browser and WordPress Cache

Browser and WordPress plugin caches can sometimes retain outdated or corrupt files that trigger the 500 error, even after the underlying issue is fixed. So before you start troubleshooting, clear your browser cache completely.

In Chrome, go to More tools > Clear browsing data and ensure "Cached images and files" is checked.

If you have a WordPress caching plugin installed, clear its cache from the plugin‘s settings page. Popular plugins like WP Rocket and W3 Total Cache have one-click options to purge the cache.

2. Check for a Corrupt .htaccess File

According to WordPress core contributor Andrew Nacin, "one of the most common causes of the 500 internal server error in WordPress is a corrupt or poorly configured .htaccess file."

To check if a faulty .htaccess file is the issue:

1. Connect to your site via FTP or your hosting control panel‘s file manager.
2. Locate the .htaccess file in your WordPress site‘s root directory (public_html or www).
3. Download the .htaccess file to your computer as a backup.
4. Rename the original file to .htaccess_old.

Now try loading your site. If the 500 error has disappeared, you‘ve identified the culprit.

To create a new, clean .htaccess file, log into your WordPress dashboard and go to Settings > Permalinks. Without making any changes, click "Save Changes." This will generate a new .htaccess file with the proper rewrite rules.

If you can‘t access your WordPress dashboard due to the error, you can create a new .htaccess file manually via FTP. Open a plain text editor, paste in the default WordPress .htaccess directives, and save the file as .htaccess.

Default WordPress .htaccess file contents:

# BEGIN WordPress
RewriteEngine On
RewriteRule .* - [E=HTTP_AUTHORIZATION:%{HTTP:Authorization}]
RewriteBase /
RewriteRule ^index.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
# END WordPress

Upload this file to your site‘s root directory, overwriting the one you renamed earlier. Remember to go to the Permalinks settings and re-save once you regain access to the dashboard to regenerate any custom rewrite rules.

3. Increase Your Site‘s PHP Memory Limit

The 500 internal server error can also arise when a script exhausts your site‘s PHP memory limit. By default, WordPress allocates 32MB of memory to PHP, but some poorly coded plugins and themes can push past that limit.

You can tell if a site is exceeding its PHP memory limit by enabling WordPress debug mode (which we‘ll cover in step 6). If you see an error message like "Allowed memory size of xxxxxx bytes exhausted," you‘ve found the culprit.

To increase your site‘s PHP memory limit:

1. Connect to your site via FTP.
2. Download the wp-config.php file.
3. Open the file in a text editor.
4. Add the following code snippet just before the line that says "That‘s all, stop editing!"

define( ‘WP_MEMORY_LIMIT‘, ‘256M‘ );

Save the file and re-upload it to your server, overwriting the original wp-config.php file.

Most of the time, bumping the memory limit to 256MB resolves the issue. If you still see the error, try increasing it to 512MB.

Just remember that allocating more PHP memory is a temporary fix. As WordPress consultant Jon Brown points out, "Constantly increasing memory is an inefficient way to solve the problem and can lead to poor site performance. It‘s crucial to find and fix any memory-hogging plugins or themes."

4. Deactivate All WordPress Plugins

Plugin conflicts are the most common reason for WordPress white screens and internal server errors. If your site‘s 500 error appeared after installing or updating a plugin, that‘s the first place to look. But even if you haven‘t touched your plugins recently, it‘s still smart to rule them out as the cause.

To quickly determine if a plugin is the problem, deactivate all your WordPress plugins at once. You can do this via FTP by renaming the plugins folder:

1. Connect to your site via FTP.
2. Navigate to the wp-content folder.
3. Rename the plugins folder to plugins.deactivate or plugins.old.

Now visit your site and see if the error disappears. If it does, you‘ve confirmed a plugin is at fault.

Rename the folder back to plugins to get your plugins back. Then deactivate each plugin individually, reloading the site after each one to pinpoint which plugin is causing the issue.

If you can still access your WordPress admin area, you can bulk deactivate all plugins from the Plugins page. Select all the plugins, choose "Deactivate" from the dropdown, and click "Apply."

Once you‘ve found the offending plugin, you can either leave it deactivated, contact the plugin developer for help, or find an alternative plugin.

5. Switch to a Default Theme

While not as common as plugin issues, your WordPress theme can also trigger a 500 error if its code is buggy or poorly written. To check if your theme is the problem, switch to a default WordPress theme like Twenty Twenty-Three.

You can do this from the Appearance > Themes screen in your WordPress dashboard if you have access. If not, access your site via FTP, navigate to the wp-content/themes folder, and rename your current theme‘s folder to theme-name.old.

WordPress will automatically revert to a default theme. If this resolves the 500 error, your theme was the issue.

Reach out to the theme developer for guidance or consider switching to a different theme. Always run theme updates on a staging site first to check for errors before pushing to production.

6. Enable WordPress Debug Mode

WordPress has a built-in debug mode that logs errors and warnings to help with troubleshooting. Enabling debug mode can give you more insight into what‘s causing the 500 error.

To turn on debug mode:

1. Connect to your site via FTP.
2. Download the wp-config.php file.
3. Open the file in a text editor.
4. Look for this line: define( ‘WP_DEBUG‘, false );. If you can‘t find it, add it just before the line that says "That‘s all, stop editing!"
5. Change false to true so it looks like this: define( ‘WP_DEBUG‘, true );
6. Save the file and re-upload it to your server.

With debug mode enabled, WordPress will start logging errors to a debug.log file in the wp-content directory.

After triggering the 500 error again, download the debug.log file via FTP and open it in a text editor. Look for any error messages that point to a specific file, function, or line of code.

For example, if you see an error message like "PHP Fatal error: Uncaught Error: Call to undefined function xyz() in /public_html/wp-content/themes/my-theme/functions.php:543", you know the issue is with the functions.php file in your theme.

Keep in mind that the debug log can get quite lengthy and contain many notices and warnings that aren‘t related to the 500 error. Focus on the most recent entries and look for any mention of "fatal error," "exception," or specific files.

Remember to disable debug mode when you‘re done troubleshooting. Leaving it enabled on a live site can expose sensitive information.

7. Reupload Core WordPress Files

Occasionally, WordPress core files can get corrupted due to failed updates, hackers, or server issues. If none of the above steps have fixed the 500 error, you can try replacing the core WordPress files with fresh copies.

Don‘t worry – this won‘t affect your site‘s content, themes, or plugins.

To replace the core WordPress files:

1. Download the latest version of WordPress from WordPress.org.
2. Extract the ZIP file.
3. Delete the wp-content folder from the extracted files (this is where your themes, plugins, and uploads live).
4. Connect to your site via FTP.
5. Upload the remaining extracted files to your site‘s root directory, overwriting the existing files.

If the 500 error persists after replacing the core files, you can rule out WordPress core as the cause.

8. Contact Your Web Host‘s Support

If you‘ve worked through all the above steps and still can‘t resolve the 500 error, it‘s time to call in reinforcements. Reach out to your web hosting provider‘s support team and provide them with as much information as possible, including:

• When the error first occurred
• What changes you made to your site right before the error appeared (installed a new plugin, updated WordPress, etc.)
• Steps you‘ve already taken to troubleshoot the issue
• Relevant error messages from your debug log

Managed WordPress hosts like WP Engine, Flywheel, and Kinsta have WordPress experts on staff who can help you pinpoint the cause of the 500 error and resolve it.

Your host‘s support team can also check the server error logs for clues and optimize your server‘s configuration settings if needed.

Tips to Prevent WordPress 500 Internal Server Errors

While you can‘t completely prevent 500 errors from ever occurring, following WordPress best practices will minimize the risk:

• Choose a reputable managed WordPress host that offers automatic updates, daily backups, and malware scanning.
• Only install plugins and themes from trusted sources like the official WordPress repository or well-known marketplaces.
• Keep your WordPress version, plugins, and themes updated to ensure compatibility and patch security vulnerabilities. Consider setting up automatic updates.
• Run major updates on a staging site first to test for issues before pushing to production.
• Regularly optimize your WordPress database to keep it lean and efficient.
• Monitor your site‘s resource usage and performance with a tool like New Relic or GTmetrix. Look for plugins or themes that consume excessive CPU or memory.
• Implement basic WordPress security measures like strong passwords, two-factor authentication, and limiting login attempts.
• Schedule regular backups of your WordPress site files and database. Store the backups off-site or in the cloud for easy restoration.
• Use a security plugin like Wordfence, Sucuri, or iThemes Security to scan for malware, brute force attacks, and other threats.

By taking a proactive approach to WordPress maintenance and security, you can head off many common causes of the 500 internal server error before they bring your site down.

Wrapping Up

Encountering a 500 internal server error on your WordPress site is no small headache, especially when you‘re not sure where to start troubleshooting. But with this step-by-step guide in hand, you should be well-equipped to track down the source of the problem and implement a fix.

Remember to always back up your site before making any changes, and don‘t be afraid to call in professional help if you get stuck. The WordPress community is full of knowledgeable developers and support experts who can lend a hand.

Here‘s hoping you‘ll have your site back up and running in no time!

For more in-depth WordPress tutorials and tips, be sure to check out the WPBeginner blog and YouTube channel. Happy troubleshooting!