# UNAUTHENTICATED — 401 Unauthorized

# 401 Unauthorized

Authentication failed. The request did not include valid credentials.

## Category

`authentication`

## Retryable?

**No.** Fix the credential issue before retrying.

## Common Causes

- Missing `Authorization` header
- Malformed header (e.g., missing `Bearer` prefix)
- Expired or revoked API key
- Using a sandbox key against the production endpoint (or vice versa)


## Error Codes

Each code below is an anchor. The `type` URI on a problem-detail response points straight at it, so
dereferencing `type` lands on the exact code rather than the top of this page.

### INVALID_SESSION

The session token is missing, malformed, or no longer valid.

**What to do:** Create a new session and retry with its token.

## Example

```json
{
  "type": "https://developer.gett-tech.com/errors/UNAUTHENTICATED",
  "title": "Unauthorized",
  "status": 401,
  "detail": "Authentication required. Provide a valid API key (Bearer zpka_...).",
  "instance": "/v1/marketfront/stores/discover",
  "requestId": "req_abc123",
  "timestamp": "2026-03-11T14:30:00.000Z",
  "errorCode": "UNAUTHENTICATED",
  "errorCategory": "authentication",
  "retryable": false
}
```