# Use DPoP nonce

The KeenAuth APIs return this problem type with HTTP status 401 (Unauthorized).

## Problem type

| Field | Value |
|---|---|
| Type URI | `https://docs.keenauth.com/errors/use_dpop_nonce` |
| Code | `use_dpop_nonce` |
| HTTP status | 401 Unauthorized |
| Title | Use DPoP nonce |

## Meaning

The proof carries no cell nonce or an old one; create a new proof with the value of the `DPoP-Nonce` response header (RFC 9449 §8).

## Example response

Example response body. `detail` is a human-readable English description that is not meant for end users; `instance` identifies the request.

```json
{
  "type": "https://docs.keenauth.com/errors/use_dpop_nonce",
  "title": "Use DPoP nonce",
  "status": 401,
  "code": "use_dpop_nonce",
  "detail": "...",
  "instance": "urn:idp:request:<request_id>"
}
```

All error codes: [Error reference](/docs/errors).