# key_required

URL: /evidence/errors/key_required · Id: `error:key_required`

> The Offer requires a Key, and the call presented none.

The `key_required` [Problem](/evidence/errors) means: the Offer requires a [Key](/callers/keys), and the call presented none.

## Answer
| Status | Title |
| --- | --- |
| 401 | Unauthorized |

```json
{
  "type": "about:blank",
  "title": "Unauthorized",
  "status": 401,
  "detail": "What went wrong, in words.",
  "code": "key_required"
}
```

## Fix
Send the Key as `X-Api-Key`, or as `Authorization: Bearer <key>`.