Page Not Found Error is commonly known on the web as 404 Not Found. It is an HTTP status code indicating that the page a user is trying to access cannot be found on the server. This error is not simply a message created by the browser; it occurs when the server reports that no valid resource exists at the requested address. Users may see messages such as “Page not found”, “404 Not Found” or a similar error screen. This situation can negatively affect both user experience and SEO performance.
There can be many different causes of 404 errors. Incorrect URLs in website menus, buttons, internal links or backlinks from external websites can lead to this issue. Similarly, deleting a page, changing the URL structure, updating file names or moving a page to a different folder can also create a 404 error. For example, if the “/help” page is changed to “/help-center”, users who visit the old URL will see a 404 error unless a proper redirect is implemented.
Moving website files to the wrong folders or changing the directory paths of images, PDFs, CSS and JavaScript files can also cause page or resource not found errors. Connection paths should be checked carefully, especially after a site migration, infrastructure change, theme update or URL revision. If old links are not updated according to the new structure, users may encounter 404 errors in different parts of the website. This can reduce trust in the site and cause visitors to leave the page.
The first step in solving 404 errors is to identify the source of the problem correctly. If a page has been permanently moved to a new address, a 301 redirect should be set from the old URL to the new URL. If the page has been moved temporarily or the change is short-term, different redirect types may be considered. However, if a deleted page no longer has a relevant replacement, it may be better to present a useful custom 404 page and guide users to related categories, a search field or the homepage.
Website links should be checked regularly. Broken links in menus, footers, breadcrumbs, product links, blog posts and campaign pages weaken the user experience. On large websites, identifying these errors manually can be difficult. For this reason, Google Search Console, Google Analytics 4, crawler tools and log analysis can be used to detect 404 errors. In particular, page indexing and crawl reports in Search Console help show which URLs Google identifies as problematic.
From an SEO perspective, 404 errors do not always mean a critical problem. It is normal for some deleted or no longer available pages to return a 404 status. However, if important pages that receive traffic, have backlinks, generate sales or are heavily linked internally return 404 errors, this can cause significant visibility and performance loss. Such pages should be redirected to the closest relevant page or the content should be recreated. Redirecting large numbers of unrelated pages to irrelevant destinations is not a proper solution for user experience or SEO.
A well-designed 404 page can guide users to the right place instead of losing them completely. This page may include a short and clear explanation, a link back to the homepage, an internal search field, popular categories or support links. In this way, users can continue navigating the website even if the page they were looking for is not found. Properly managed Page Not Found Errors help protect technical SEO health, improve user experience and reduce lost traffic.