Troubleshooting 500 Internal Server Errors

What is a 500 Internal Server Error?

A 500 Internal Server Error is a generic HTTP status code indicating that something went wrong on the server, but the server can't be more specific about what the problem is.

Unlike 404 errors (which tell you a page wasn't found), 500 errors don't reveal the actual cause. This makes them frustrating to debug, but also means there are several common places to look.

Why 500 Errors Are Critical

500 errors completely block users from accessing your content. If search engine bots encounter them repeatedly, it can hurt your indexing and rankings.

Common Causes of 500 Errors

1. Corrupted .htaccess File

The .htaccess file controls server behavior for Apache servers. A syntax error or invalid directive will cause 500 errors site-wide.

Quick fix: Rename .htaccess to .htaccess_backup and see if the site loads.

2. PHP Errors or Timeouts

Syntax errors in PHP code, memory limit exceeded, or scripts that take too long to execute can all trigger 500 errors.

3. Incorrect File Permissions

Files and directories need specific permissions. Typically:

Files: 644
Directories: 755
PHP files should never be 777

4. Plugin or Theme Conflicts (WordPress)

Faulty plugins or themes are the #1 cause of 500 errors on WordPress sites, especially after updates.

5. Database Connection Issues

If your site can't connect to its database (wrong credentials, database server down, or corrupted tables), it may return 500.

6. Server Resource Limits

Exceeding your hosting plan's memory, CPU, or process limits can cause the server to error out.

Step-by-Step Troubleshooting

1 Check Server Error Logs

The error log reveals the actual cause. Look in:

# Apache
/var/log/apache2/error.log

# Nginx
/var/log/nginx/error.log

# cPanel
~/public_html/error_log

2 Test .htaccess

Temporarily rename or remove your .htaccess file:

mv .htaccess .htaccess_backup

If the site works, the issue is in your .htaccess. Review it line by line.

3 Increase PHP Memory Limit

Add to php.ini, .htaccess, or wp-config.php:

# php.ini
memory_limit = 256M

# .htaccess
php_value memory_limit 256M

# wp-config.php (WordPress)
define('WP_MEMORY_LIMIT', '256M');

4 Check File Permissions

Reset permissions to standard values:

# Directories
find /path/to/site -type d -exec chmod 755 {} \;

# Files
find /path/to/site -type f -exec chmod 644 {} \;

5 Disable Plugins (WordPress)

If you can't access wp-admin, rename the plugins folder via FTP:

mv wp-content/plugins wp-content/plugins_backup

Then reactivate plugins one by one to find the culprit.

6 Test Database Connection

Verify your database credentials are correct in your config file (wp-config.php, .env, etc.).

Preventing 500 Errors

Test changes in staging - Never push untested code to production
Keep backups - Daily backups let you quickly restore a working state
Monitor uptime - Get alerts when your site goes down
Update carefully - Test plugin/theme updates on staging first
Use error logging - Enable detailed logging to catch issues early

Monitor Your Site's Health

Regularly check your important URLs for 500 errors before users report them. URL Status Checker can scan up to 100 URLs at once to find server errors.

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Other 5xx Server Errors

The 500 error is just one of several server-side error codes:

501 Not Implemented - Server doesn't support the request method
502 Bad Gateway - Server received invalid response from upstream
503 Service Unavailable - Server temporarily unavailable (maintenance/overload)
504 Gateway Timeout - Upstream server didn't respond in time

View all 5xx error codes →

Check Your Site for Server Errors

Scan your important URLs in bulk to catch 500 errors before they hurt your SEO.

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