---
title: "Fix: Soft 404 (Unknown URLs Return 200 Instead of 404)"
description: "A soft 404 is an error page that returns HTTP 200. Test a random URL with curl and make unknown paths return a real 404 on Nginx, Apache or Next.js."
url: https://seenlens.com/fixes/soft-404-unknown-urls
last_updated: 2026-11-06
---

# Soft 404: unknown URLs return 200, how to fix it

A soft 404 is a page that looks like an error but returns HTTP 200. Your site has the problem when a made up URL answers 200. The cause is a catch all route or a redirect to the home page. Return status 404 for paths that do not exist. The change takes 10 to 30 minutes.

By SeenLens. Last updated: 2026-11-06

## What this check tests

SeenLensBot requests one made up path at the root of your host. The path starts with `claude-seo-404-probe-` followed by random characters, so you may see it in your logs. It follows redirects.

| Final status | Result |
| --- | --- |
| 200 | Warn: a catch all answers every path |
| 404, 410 or another 4xx or 5xx status | Pass |
| 202, 403, 429 or 503 | Not tested: a firewall may have answered |

A redirect from unknown URLs to the home page ends in 200, so it counts as a catch all. A catch all also makes files such as `llms.txt` look present when they are not.

## What is a soft 404?

Google defines a soft 404 as a page that returns a success code (2xx) while its content suggests an error, such as an empty page or an error message. Search Console then shows a soft 404 error. Google treats real 404 and 410 answers the same: it removes a previously indexed URL from the index and slowly crawls it less often. A 2xx answer does not guarantee indexing.

## How to confirm the problem

```text
curl -sIL -o /dev/null -w "%{http_code}\n" https://example.com/this-page-does-not-exist-12345
```

The command must print 404 or 410. It printing 200 is the problem.

## How to fix it

Find the catch all rule and make it return 404 for paths that have no page.

```text
# Nginx: return 404 when no file matches
location / {
    try_files $uri $uri/ =404;
}

# Not this (every unknown path becomes the app shell with status 200):
# try_files $uri $uri/ /index.html;
```

- **Apache:** remove a catch all `RewriteRule` that maps every path to `index.html`, or limit it to known app routes. Use `Redirect gone "/old-page"` to return 410 for a removed page.
- **Next.js (App Router):** unmatched URLs show the root `app/not-found` page with status 404. In a route, call `notFound()` when the record does not exist. Before streaming starts Next.js returns 404. After streaming starts the status stays 200, so call `notFound()` before you stream content (docs updated 2026-10-06).
- **Vercel:** remove a `rewrites` entry in `vercel.json` that sends every path to one page.
- **Single page apps:** Google advises redirecting to a server side 404 URL or adding a `noindex` tag to the error view. The better fix is a server that returns 404.
- **WordPress and Shopify:** both return 404 for unknown URLs by default. Look for a plugin, app or redirect rule that sends unknown paths to the home page.

Redirect a removed page to a close replacement with a 301 only when a good match exists. Otherwise return 404 or 410.

## How to verify the fix

1. Run the curl command again. Expect 404.
2. Open the page in a browser and check that the error page helps visitors, with a link to the home page.
3. Check that your real pages still return 200.

[Run the free SeenLens scan on your page](https://seenlens.com/)

## Does a soft 404 hurt my site?

### Does a 404 error mean I was blocked?

No. A 404 means the server found no page at that URL. A block usually shows 403, 429 or a challenge page. See the [firewall fix](https://seenlens.com/fixes/ai-crawlers-blocked-by-waf) for those.

### How long does a 404 error last?

It lasts until you publish a page at that URL. Google gradually crawls a URL that returns 404 less often and drops it from the index.

## When can you ignore it?

Rarely. A catch all that serves a real page for every path is a design choice for some single page apps, but it creates soft 404s and breaks discovery files. Plan to move the 404 decision to the server.

## Related checks

- [Crawlers cannot load the page](https://seenlens.com/fixes/ai-crawlers-cannot-load-page)
- [Content needs JavaScript](https://seenlens.com/fixes/content-needs-javascript)
- [Add a canonical URL](https://seenlens.com/fixes/add-canonical-url)
- [Add llms.txt](https://seenlens.com/fixes/add-llms-txt)

## Sources

- [Google Search Central: HTTP status codes, network and DNS errors](https://developers.google.com/search/docs/crawling-indexing/http-network-errors) (soft 404 definition, 404 and 410 handling, checked 2026-11-06)
- [Google Search Central: soft 404 errors](https://developers.google.com/search/docs/advanced/crawling/soft-404-errors) (checked 2026-11-06)
- [Google Search Central: JavaScript SEO basics](https://developers.google.com/search/docs/crawling-indexing/javascript/javascript-seo-basics) (single page apps and soft 404s, checked 2026-11-06)
- [Next.js: not-found.js](https://nextjs.org/docs/app/api-reference/file-conventions/not-found) (404 status and streaming, updated 2026-10-06)
- [Apache: mod_alias Redirect](https://httpd.apache.org/docs/2.4/mod/mod_alias.html) (gone keyword returns 410, checked 2026-11-06)
- [nginx: ngx_http_core_module](https://nginx.org/en/docs/http/ngx_http_core_module.html) (try_files, checked 2026-11-06)