A 404 error is an HTTP status code that means the page you're trying to reach on a website could not be found on the server. It's one of the most common client-side errors, indicating that while the server itself is reachable, the specific page or file is missing or unavailable.

This typically happens for a few reasons:

• The page has been deleted or moved without a proper redirect.
• The URL was typed incorrectly or contains a typo.
• A link on the site (or from another site) is broken or outdated.
• The page's permissions prevent public access.

What can you do as a visitor?
First, double-check the URL in your browser's address bar for mistakes. Try refreshing the page. Often, you can navigate back to the site's homepage and search for the content you need. If you found the broken link on another website, you might consider informing the site owner.

What should you do as a website owner?
If this error appears on your site, it's crucial to fix it to improve user experience and SEO.

1. Set up a custom 404 error page that guides visitors back to working parts of your site.
2. Use 301 redirects to send traffic from old URLs to new, relevant pages.
3. Regularly check for and fix broken links using online tools or plugins.
4. Ensure your internal linking structure is correct after any site updates.

A well-handled 404 page can turn a frustrating dead-end into a helpful detour for your visitors.