Fixing 404 Page Not Found Errors for Posts, Pages, and Categories in WordPress Permalinks

A classic WordPress anomaly occurs when your homepage loads perfectly, but clicking on any blog post, custom page, or category yields a cold 404 Not Found error. This almost always indicates that your web server’s URL rewriting engine (Apache mod_rewrite or Nginx) is out of sync with WordPress’s internal rewrite rules.

The 10-Second Fix: Flushing Rewrite Rules

In 90% of cases, simply forcing WordPress to regenerate its internal rewrite cache solves the issue:

1. Log in to your WordPress dashboard.
2. Navigate to Settings > Permalinks.
3. Do not alter any settings. Scroll directly to the bottom and click Save Changes.
4. This single click triggers the internal flush_rewrite_rules() function, writing a fresh ruleset to your .htaccess file or database.

For Nginx Servers: The Missing try_files Directive

Unlike Apache, Nginx does not use .htaccess. If your Nginx server block is missing the proper routing directive, requests for non-existent files are dropped instead of routed to index.php. Ensure your Nginx configuration includes:

location / {
    try_files $uri $uri/ /index.php?$args;
}

Reload Nginx (sudo nginx -s reload) to immediately resolve all 404 errors across permalinks.