> ## Documentation Index
> Fetch the complete documentation index at: https://stytch.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Not found errors

> Handling 404 errors for Fingerprint Lookup.

## 404 telemetry\_id\_not\_found errors

If the `telemetry_id` is missing from the lookup request, or we cannot find it in our records, Stytch will return a 404 `telemetry_id_not_found` [error](/api-reference/fraud/api/errors/404#telemetry_id_not_found).

This can happen for a few different reasons:

* An attacker can modify telemetry IDs to try to bypass your defenses.
* An attacker might omit telemetry IDs because they don't have a JavaScript environment.
* Your frontend implementation might have a bug involving `GetTelemetryID()`.

You should "fail closed" on 404 errors and treat them as if they were `BLOCK`.

<Note>
  See [Reference guides](/fraud-risk/development/overview) for guidance on testing your integration.
</Note>

## Not found results in the API

When you receive a 404 in the [Fingerprint Lookup](/api-reference/fraud/api/fingerprint-lookup) response, we recommend blocking the request from proceeding.

A missing or invalid telemetry ID could be a sign of an attacker trying to bypass Device Fingerprinting by generating fake telemetry IDs or not passing them into requests.

## Not found results in Protected Auth

When [Protected Auth](/fraud-risk/concepts/device-fingerprinting/enforcement/protected-auth/overview) is enabled in *Enforcement mode* and the `telemetry_id` is missing from the request or not found by Lookup, the Stytch SDK will always prevent the user's request from proceeding.