WordPress “404 Not Found” errors can be some of the most frustrating to diagnose because they often hide the underlying server or database problem. This guide provides a systematic, professional workflow for identifying and fixing these issues.
The Difference Between a WP-404 and a Server-404
- WP-404: Your site is loaded, but WordPress can’t find the content. This is usually a database or slug issue.
- Server-404: The server itself (Apache or Nginx) doesn’t even know WordPress exists at that URL. This is often an `.htaccess` or file permission error.
1. The Quickest Fix: Refresh Your Permalinks
If your 404s appear after changing a plugin or moving your site, the first step is always to flush the permalink cache:
- Go to **Settings > Permalinks** in your WP Admin.
- Simply click **”Save Changes”** without changing anything. This forces WordPress to rebuild the internal redirect rules.
2. Verify the .htaccess File (Apache Only)
If refreshing permalinks doesn’t work, your `.htaccess` file might be corrupted or lack write permissions. Ensure it contains the standard WordPress block:
# BEGIN WordPress
<IfModule mod_rewrite.c>
RewriteEngine On
RewriteBase /
RewriteRule ^index\.php$ - [L]
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule . /index.php [L]
</IfModule>
# END WordPressNote: On Nginx, these rules must be handled in your server config (`nginx.conf`), as Nginx does not use `.htaccess` files.
3. Check for File Permission Issues
Sometimes the 404 is caused because the web server doesn’t have permission to read the files it’s looking for:
- Directories should generally be **755**.
- Files should generally be **644**.
- Ensure the `www-data` user (on most Linux systems) owns the WordPress directory.
4. Use WP-CLI to Find Broken Slugs
# List all published posts to check for slug mismatches
sudo -u www-data wp post list --post_status=publish --fields=ID,post_name,post_status5. Review the Apache/Nginx Error Logs
The logs are the ultimate source of truth. They will tell you exactly what file or path the server was looking for when the 404 occurred:
# Watch for 404s in real-time
sudo tail -f /var/log/apache2/error.log | grep "404"Further reading: Official WordPress .htaccess Documentation
Related: learn more about our WordPress operations approach, layered security for repeated attacks, or contact us for support.
