Everything you need to know about 404 errors

The "404 Not Found" error is one of the most recognizable and common HTTP status codes on the Internet. Whether you are a website owner, a developer, or a regular user, you have likely encountered this error more than once while browsing the web. Despite its prevalence, many people do not fully understand what a 404 error is, why it occurs, and how to fix it. In this article, we will take a detailed look at this topic, what a 404 error is, the reasons for its occurrence, and the consequences of this error for website administration. And of course, we will describe several methods for eliminating it.

Overview of Existing HTTP Status Codes

Before we look at the specifics of the 404 error code, it’s important to understand the context in which it operates: HTTP (Hypertext Transfer Protocol) status codes. These codes are standardized responses sent by servers to indicate the outcome of a client’s request. They fall into five categories, starting with a number from one to five:

    1xx: Informational responses - Indicate that the request was received and is being processed.
    2xx: Success responses - Indicate that the request was successfully received, understood, and accepted.
    3xx: Redirect messages - Indicate that the client needs to take additional action to fulfill the request.
    4xx: Client error responses - Indicate that the request contains invalid syntax or cannot be fulfilled.
    5xx: Server error responses - Indicate that the server was unable to fulfill a valid request.

Error 404 falls into the 4xx category and means that the client made a valid request, but the server cannot find the requested resource.

What is a 404 error?

Now let's take a closer look at the 404 response code.

A 404 error occurs when a client (such as a web browser) requests a resource (such as a web page) that the server cannot find. This error does not mean that the server is down or malfunctioning; rather, it indicates that the URL entered does not match any resource currently available on the server.

The full error message is usually "404 Not Found" or "Error 404 Not Found". This response is sent by the server when it cannot find the requested content. The server successfully processed the request, but the resource requested (such as a specific web page, image, or file) is not available, usually because it has been moved, deleted, or the URL was entered incorrectly.

Common Causes of 404 Errors

Several factors can lead to the occurrence of a 404 not found error:

    Broken or Dead Links: One of the most common causes is broken links, where the hyperlink directs to a URL that no longer exists. This could be due to the page being deleted or the URL structure being changed without proper redirection.
    Typo in the URL: Users often encounter 404 errors due to a simple typo in the URL. Even a small mistake in typing the web address can result in a 404 code.
    Moved or Renamed Content: When content is moved to a different URL or renamed, and the old URLs are not properly redirected, users attempting to access the old URL will receive a 404 error.
    Incorrectly Configured DNS: If the Domain Name System (DNS) is not correctly configured, it might point to the wrong IP address or an outdated server, leading to 404 errors.
    Caching Issues: Sometimes, a browser may cache a webpage's URL that has since changed, leading to a 404 error when the browser tries to load the old cached version.
    Improperly Configured Web Server: If the web server's configuration files (like .htaccess in Apache servers) are incorrectly set up, it may lead to resources not being correctly found, resulting in a 404 error.
    Content Management System (CMS) Issues: In cases where a CMS like WordPress is used, updates or plugins can sometimes disrupt URL structures, leading to 404 errors.

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Impact of 404 Errors

While a single 404 error that appears on a site may seem insignificant, frequent occurrences of such errors can have significant negative effects on a website, especially with regards to user experience and SEO (search engine optimization).

User Experience

From a user perspective, encountering a 404 error can be a frustrating experience. It interrupts the browsing flow and can create the impression that the website is poorly maintained or unreliable. This can lead to increased bounce rates, where users leave the site after viewing only one page, potentially reducing overall user engagement and greatly impacting the behavioral factors that Google takes into account when ranking a site in search results in the future.

SEO Impact

404 errors can also negatively impact a website’s SEO performance. Search engines like Google interpret frequent 404 errors as indicators of poor website maintenance. This can lead to lower rankings on search engine results pages (SERPs). Additionally, search engines may de-index pages that frequently return 404 errors, resulting in lost traffic.

However, it is important to note that not all 404 errors are bad for SEO. When handled correctly with appropriate error pages and redirects, their impact can be minimized. However, allowing too many unresolved 404 errors to occur can be detrimental to a site’s overall visibility and authority.

Methods for Troubleshooting 404 Errors

Effectively troubleshooting all 404 errors on a site requires a comprehensive approach. Here are some strategies you can use to do so:

1. Check and fix typos in URLs

Sometimes, resolving a 404 error is as simple as fixing a typo in a URL. Website administrators should regularly check the accuracy of their URLs and ensure that all internal and external links point to the correct resources.

2. Set up 301 redirects

When a web page is moved or deleted, it is important to set up a redirect (301 redirect) from the old URL to the new one. A 301 redirect is a permanent redirect that transfers the SEO value of the original URL to the new URL, helping to maintain the site’s search engine rankings.

Setting up a 301 redirect depends on your server environment: On Apache, you can do this by adding a redirect rule to your .htaccess file, while on Nginx, you need to add a rewrite rule to the "server" block configuration.

3. Use Custom 404 Error Pages

A custom 404 error page can improve the user experience by providing helpful information when a 404 error occurs. Instead of displaying a generic error message, a custom 404 page can include links to other parts of the site, a search bar, or a message encouraging users to check the URL or contact support.

Creating a custom 404 page typically involves changing the server configuration to point to a specific HTML file that serves as the error page. For example, on Apache, you would add the following line to your .htaccess file:

    ErrorDocument 404 /404.html

4. Monitor 404 Errors

Regularly monitoring your site for 404 errors allows you to quickly identify and resolve them. Tools like Google Search Console, Screaming Frog, or server logs can help you track down 404 errors on your site. Once you find them, you can take steps to fix the errors, such as setting up redirects or fixing broken links.

5. Update Internal and External Links

Broken links are a common cause of 404 errors. Regularly auditing your site for broken internal and external links ensures that users can always access the content they are looking for. Tools like Broken Link Checker can automate this process by scanning your site for broken links.

6. Check Server Configuration

Incorrect server configuration can lead to 404 errors. It is essential to ensure that your server is configured correctly and that all necessary files (such as .htaccess) are in place. This step is especially important for websites that are frequently updated or migrated.

Preventing 404 Errors

Preventing 404 errors requires constant vigilance and good website management practices. Here are some tips to reduce the likelihood of 404 errors on your site:

1. Use a reliable CMS and update it regularly

Choosing a reliable content management system (CMS) and updating it regularly can reduce the risk of 404 errors. A well-maintained CMS will ensure that your URL structure is maintained and that updates do not inadvertently create broken links.

2. Perform regular website audits

Conducting regular website audits can help identify and fix potential issues before they lead to 404 errors. This includes checking for broken links, checking that redirects are working correctly, and ensuring that your content is organized properly.

3. Maintain a consistent URL structure

Maintaining a consistent URL structure helps prevent 404 errors. Avoid renaming or moving files and pages unnecessarily. If changes are necessary, make sure the correct redirects are in place.

4. Train editors and content writers

If your site has multiple administrators or content managers, it is important to train them on best practices for linking to content. This includes checking URLs before publishing and understanding the implications of moving or deleting content.

Conclusion

Understanding the causes of 404 errors is essential for anyone involved in web development, administration, or content management. While often perceived as a minor inconvenience, frequent 404 errors can have serious implications for both user experience and SEO. By understanding the root causes of these errors and implementing strategies to prevent or fix them when they occur, you can ensure the reliability and user experience of your website.

Effective 404 error management includes regular monitoring, proper server configuration, a consistent URL structure, and the use of custom error pages. Additionally, setting up 301 redirects for moved or removed content ensures that users and search engines are directed to the correct pages, preserving the SEO value of your site.