HTTP 404 Not Found

HTTP 404 Not Found indicates a client errors response outcome.

What it means

Not Found describes how the server processed the request and what the client should do next.

Why it happens

Common triggers include protocol conditions, routing decisions, and application behavior.

Common causes

Broken internal link
Deleted page
Incorrect URL
Routing mismatch
Missing rewrite rule

How to fix it

Verify the URL
Restore the resource if it was removed unintentionally
Add or correct server routing
Set up a redirect if the page moved
Update internal links

Example request/response

GET /missing-page HTTP/1.1
Host: errorlookup.com

HTTP/1.1 404 Not Found
Content-Type: text/html

Browser/dev/server context

Use browser network tools, server logs, and APM traces together when diagnosing HTTP 404.

Related status codes

FAQ

Does 404 mean the server is down?

No. It means the resource was not found at that URL.

Should I redirect all 404 pages?

Only when there is a relevant replacement resource.