What is an HTTP 404 error?
An HTTP 404 error indicates that a web server received a valid request but could not locate the requested resource. The request reached the server successfully, but the server could not match the requested URL to an existing file, directory, or application route.
A 404 error does not mean that the server is down or malfunctioning. It means the server is reachable and working, but the specific resource does not exist at the requested location.
What is an HTTP status code?
An HTTP status code communicates the result of a request made by a client, usually a web browser. Every HTTP request generates a response that includes a numeric status code, which explains how the server handled the request.
A request can return content, redirect the client to another URL, or return an error. Behind the scenes, the web server performs several checks, including URL parsing, file lookup, rewrite rules, routing logic, and access permissions. The HTTP status code summarizes the result of this process.
For example, when a browser requests:
http://mysite
and the server redirects the request to:
https://mysite
the server responds with HTTP 301 or HTTP 302, indicating that the resource moved to another location. The browser then follows the redirect automatically.
Where HTTP 404 fits in the status code system
HTTP 404 belongs to the 4xx client error category. These status codes indicate that the server understood the request but could not fulfill it due to an issue related to the requested resource.
A 404 response means that the URL does not match any known resource. The server processed the request correctly but could not find content to return. This differs from 5xx errors, which indicate internal server failures.
How web servers process URLs
When a request reaches the web server, it follows a structured resolution process. The server parses the URL path, checks whether it maps to a physical file or directory, applies rewrite rules, and forwards the request to an application if needed.
If none of these steps result in a valid response, the server returns HTTP 404.
HTTP 404 behavior on web servers
On most web servers, requested URLs often map to the file system inside the website’s document root.
For example, when a browser requests:
https://domain.com/cats
the web server attempts to locate a matching folder or file named cats inside the document root. If the resource does not exist, the server returns an HTTP 404 error.
Incorrect document root configuration can cause 404 errors across an entire website.
LiteSpeed and .htaccess rules
LiteSpeed is the web server used on our hosting platform. LiteSpeed is compatible with Apache-style .htaccess rules and processes them in the same way.
This means that rewrite rules, redirects, and routing logic defined in .htaccess files work as expected, even though the underlying web server is LiteSpeed and not Apache.
When rewrite rules are missing, incorrect, or overridden, LiteSpeed may return 404 errors even if the application itself is correctly configured.
When URLs do not represent files or folders
Many modern websites use URLs that do not correspond to physical files or directories. Instead, a single entry point script handles all requests and determines what content to return.
In this setup, the web server should not attempt to locate files on disk. Instead, it forwards requests to an application-level router that decides whether the requested resource exists.
PHP-based frameworks and content management systems rely heavily on this routing model.
Rewrite rules and routing logic
To support dynamic routing, the web server uses rewrite rules defined in .htaccess.
A common configuration looks like this:
Rewrite Engine On
RewriteCond %{REQUEST_FILENAME} !-f
RewriteCond %{REQUEST_FILENAME} !-d
RewriteRule ^(.*)$ index.php/$1 [L]
This configuration tells the web server that if the request does not match an existing file or directory, it should forward the request to index.php. The application then processes the request and returns content or a 404 response.
WordPress rewrite rules and HTTP 404 errors
WordPress relies on rewrite rules to map URLs to posts, pages, and custom content types. These rules live in the .htaccess file and allow WordPress to handle URLs that do not match physical files.
When WordPress rewrite rules are missing or outdated, the site may return HTTP 404 errors for existing pages.
Common causes include:
- permalinks not flushed after changes
- corrupted or missing
.htaccessrules - incorrect document root configuration
- plugin or theme conflicts affecting routing
Refreshing permalink settings in the WordPress admin panel often regenerates the correct rewrite rules and resolves 404 errors.
Application-level 404 errors
Not all 404 errors originate from the web server. Applications can intentionally return HTTP 404 when a requested resource does not exist in the database, when a page slug is invalid, or when access logic determines the content should not be available.
In these cases, the web server delivers the application response correctly, and the application itself signals that the resource is unavailable.
Common causes of HTTP 404 errors
HTTP 404 errors usually result from incorrect URLs, deleted or renamed content, broken internal links, missing rewrite rules, incorrect document root paths, or application routing issues.
Understanding where request processing fails helps identify whether the issue occurs at the web server level or inside the application.
Why HTTP 404 errors matter
Frequent 404 errors can confuse visitors, break navigation, reduce crawl efficiency, and make site maintenance more difficult. While occasional 404 responses are normal, recurring errors often point to configuration or routing problems that require attention.
Summary
An HTTP 404 error indicates that the web server successfully received a request but could not find the requested resource. The cause usually relates to URL structure, rewrite rules, document root configuration, or application routing logic rather than server failure. Understanding how LiteSpeed and .htaccess rules process requests helps diagnose and resolve these issues more effectively.
Need help?
If 404 errors appear unexpectedly or affect multiple pages, review recent URL changes, rewrite rules, and document root settings. Server logs can help identify whether the issue occurs during request handling or application routing.
