404 error, what it is and how to correct it

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Introduction

When your browser displays a "404 Not Found" message, this indicates that the HTTP server has been unable to locate the requested resource. In other words, the page or web content you are looking for is not available on the server.

HTTP response codes are indicators of whether or not an HTTP request has been executed successfully. Classified as "Client errors (400 - 499)", the 404 code is one of these codes, specifically indicating an inability to find the requested resource.

Where do 404 errors come from? How are they generated?

The reasons behind a 404 response can be varied:

Website migration or redesign

During a website redesign or migration, a change of domain name or URL structure without adequate redirection can lead to a large number of 404 errors.

Day-to-day site management

In addition to migrations, a 404 error can occur when a page or web resource is deleted. In addition, any change in URL syntax can cause an error, for example :

• Old syntax: example.com/product-category
• New syntax: example.com/category-products

Some content management systems (CMS) do not automatically handle these syntax changes, which can lead to 404 errors for old URLs.

Incorrect links from other websites

Site publishers cannot always control incorrect links embedded or shared by users on other websites. This can lead to situations where a correct URL is transformed into an incorrect URL, for example :

• Correct syntax: example.com/product-category
• Incorrect syntax: example.com/productcategory

URL entry errors

Manually modifying the syntax of a URL by adding extra characters can result in a 404 error, as the server cannot find a resource corresponding to this incorrect URL.

The impact of 404 errors on SEO:

404 errors are not directly detrimental to SEO, but they can have several implications:

Loss of popularity and URL history

When you delete a page containing external links, that page becomes a 404 error, which means that it stops passing on its popularity to the rest of the site.

Impact on the quality of crawl by indexing robots

If your site contains a large number of pages with a 404 error, there is a risk that crawlers will spend time crawling irrelevant resources instead of concentrating on pages that are essential for your SEO strategy.

Degradation of the user experience

Encountering a 404 error can be frustrating for users when browsing a site. To improve this experience, we recommend customising your 404 error page. You can find some good ideas by consulting the top-rated custom error pages on Google.

How can I identify a resource returning a 404 error?

There are several SEO tools for detecting 404 errors on a site:

Google Search Console

In the "Coverage" > "Excluded" > "Not found (404)" section. However, it should be noted that the data in Google Search Console is limited, with a maximum export of 1,000 lines. If you have a large number of URLs in 404 error, you will first need to correct this first batch of 1,000 URLs before you can consult the following ones.

Crawl analysis tools such as Screaming Frog, Botify, OnCrawl, etc.

These tools can detect only resources linked to the site during the crawl.

SEO tools such as Ahrefs, Majestic SEO, Semrush, etc.

These tools do not provide exhaustive data because they only identify resources from third-party sites. With Semrush, only URLs returning a 404 error and linked to the site will be detected.

Server logs

Server logs offer a reliable and exhaustive source of information. The longer the retention period, the more exhaustive the data. The logs can be used to find out which resources with a 404 error have been visited by users and indexing robots (Googlebot, Bingbot, etc.). Just make sure that the format of the server logs includes the recovery of response codes to identify URLs in 404 error.

How do I correct a 404 error?

Fixing a 404 error is not difficult, but it can be time-consuming. Simply redirect these non-existent URLs to new pages with a 301 status code. For each page returning a 404 error, you need to indicate the new target page, ideally the one that is semantically closest to the old URL. If the deleted page does not have an exact match, you can redirect it to the category page from which it was linked. Avoid massive redirections to the URL of the home page, as this could harm its performance.

It is important to note that you are not obliged to systematically redirect a URL returning a 404 error. To decide, make sure that the URL does not have a strong SEO impact (natural visits, backlinks, positioned keywords, etc.). If the URL has an SEO history, redirect it to 301 to avoid losing its reputation. Otherwise, you can use status code 410 to indicate that the URL is definitively "Gone". Code 410 informs the browser that the page has existed but that the resource is no longer permanently available.

Conclusion

You now know how to :

• Interpret a 404 Not Found error message and understand the implications it may have for your website.
• Identify the different sources of a 404 error, whether it's a site migration, day-to-day management, incorrect links orinput errors.
• Assess theimpact of 404 errors on SEO, particularly in terms of loss of popularity, crawl quality and user experience.
• Use various SEO tools such as Google Search Console, Screaming Frog and server log analysis to identify problematic resources.
• Apply best practice to correct a 404 error, using 301 redirects or status code 410 where appropriate.

🚀 By understanding and acting on these elements, you can significantly improve the health of your website and provide a smooth and satisfying browsing experience for your users. 🌐

🙏 Thank you for reading this article to the end! If you have any questions, suggestions, or would like to share your experience with 404 errors, please feel free to leave a comment below. Your feedback is valuable and can help other readers navigate the vast ocean that is the internet! 💬