Detailed and structured explanation of the HTTP 404 Not Found Error, covering its meaning, causes, troubleshooting steps, and prevention methods.

Understanding the HTTP 404 Not Found Error

The HTTP 404 Not Found error is a client-side error that occurs when the server cannot find the requested page, file, or resource. This means that the URL entered by the user is incorrect, the resource has been deleted, moved, or is temporarily unavailable.

Unlike server-side errors (such as 500 Internal Server Error), a 404 error indicates that the issue is on the client’s side (e.g., incorrect URL input) or a missing resource on the server.

Common Causes of HTTP 404 Not Found Errors

The 404 error can occur due to several reasons. Below are the most common causes:

1. Incorrect URL or Typo in Address

A simple typo in the URL can lead to a 404 error.
Example:
🔴 Incorrect: https://example.com/aboutt-us ✅ Correct: https://example.com/about-us
Ensure that uppercase and lowercase letters are correct, as some servers are case-sensitive.

2. The Page or Resource Has Been Moved or Deleted

If the requested page was removed from the website, the server cannot find the resource, leading to a 404 error.
If the page was moved to a different URL without setting up a redirect, users trying to access the old URL will see a 404 error.

3. Missing or Broken Links (Dead Links)

Links that point to nonexistent or deleted pages result in 404 errors.
Broken links can exist due to:
- Manual errors when adding links.
- Pages that were deleted without updating internal links.

4. Improper Redirects or Configuration Issues

If a redirection rule in .htaccess or server configuration is incorrect, it may cause the server to redirect users to a non-existent page.

5. DNS or Cache Issues

Sometimes, the domain name system (DNS) has outdated records, causing a 404 error.
Browser cache or corrupted cookies might store an old version of a site where a page no longer exists.

6. Incorrect File Permissions

If the server lacks permissions to access the requested file or directory, it may respond with a 404 error instead of a 403 Forbidden error.

7. Website Restructuring or CMS Changes

If a website switches from WordPress to another CMS or modifies its URL structure, old links may lead to 404 errors if not properly redirected.

How to Fix an HTTP 404 Not Found Error

If you encounter a 404 error, follow these step-by-step solutions to troubleshoot and resolve the issue.

🔎 Step 1: Check for URL Errors

Ensure that the URL is correctly typed and formatted.
Pay attention to:
- Misspelled words (e.g., /contactt instead of /contact)
- Wrong domain extension (.com vs. .net)
- Incorrect URL slugs (/blog/post-title vs. /blog/post_title)

👉 Try retyping the URL manually instead of copying and pasting.

🔎 Step 2: Refresh or Reload the Page

Press Ctrl + R (Windows) or Cmd + R (Mac) to refresh the page.
If the website was temporarily unavailable, a simple refresh might resolve the issue.

🔎 Step 3: Check If the Page Has Moved

If the page was moved to a new URL, try to find its new location by:
- Visiting the homepage and navigating through the menu.
- Using the search bar (if available).
- Checking the sitemap.xml (e.g., https://example.com/sitemap.xml).

🔎 Step 4: Clear Browser Cache and Cookies

Outdated or corrupted cache files may store old URLs, causing 404 errors.
Clear the browser cache:
- Google Chrome:
  - Press Ctrl + Shift + Delete (Windows) or Cmd + Shift + Delete (Mac).
  - Select “Cached images and files” and clear data.

🔎 Step 5: Use a Different Browser or Device

If the issue persists, try opening the website on another browser (e.g., switch from Chrome to Firefox).
If the page loads correctly in another browser, the problem may be related to your browser cache or extensions.

🔎 Step 6: Verify Internal Links

If you are a website owner, check for broken internal links that point to deleted or moved pages.
Use tools like:
- Google Search Console (Coverage Report)
- Broken Link Checkers (e.g., Dead Link Checker, Screaming Frog)

🔎 Step 7: Restore Missing Pages or Set Up Redirects

If you are a website administrator:

Restore the missing page (if it was accidentally deleted).
Set up a 301 Redirect if the page was moved:
- For Apache servers (via .htaccess): Redirect 301 /old-page.html https://example.com/new-page.html
- For Nginx (in nginx.conf): rewrite ^/old-page$ /new-page permanent;

🔎 Step 8: Check Server Configuration Files

For Apache servers, verify the .htaccess file for incorrect rules: RewriteEngine On RewriteCond %{REQUEST_FILENAME} !-f RewriteRule . /index.php [L]
For Nginx servers, confirm that the correct file path exists in the configuration.

🔎 Step 9: Check File and Folder Permissions

Ensure that the server has read permissions for files:

chmod 644 /var/www/html/index.html
chmod 755 /var/www/html/

If permissions are set incorrectly, the server might return a 404 error.

🔎 Step 10: Contact Website Administrator

If you don’t own the website and all fixes fail, reach out to the site owner or support team for assistance.

How to Prevent HTTP 404 Not Found Errors

To avoid 404 errors in the future, follow these best practices:

✅ Use 301 Redirects
If you move or rename a page, always set up a redirect to the new location.

✅ Regularly Check for Broken Links
Use tools like Google Search Console or Ahrefs to monitor dead links.

✅ Ensure Proper URL Structure
Avoid changing URL slugs frequently, as it can break links.

✅ Maintain a Custom 404 Page
Create a user-friendly 404 page that helps visitors find what they’re looking for.

✅ Keep Website Navigation Updated
Make sure menus, sitemaps, and internal links point to correct pages.

“404 Not Found” – The requested page or resource could not be found.