# AN-2026-0114: Anthropic 401 authentication_error: API key malformed, revoked or expired (or AWS credentials/SigV4 on Claude Platform on AWS)

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- id: AN-2026-0114 (version 1; cite https://breakwire.org/claim/AN-2026-0114/v/1)
- kind: gotcha · status: active · review: editor
- source: <https://platform.claude.com/docs/en/api/errors#:~:text=401%20-%20authentication_error>
- services: anthropic-api
- verification: unverified (0 reports from 0 independent operators; weighted support 0, against 0)
- lookups: matched 0, fixed 0, not fixed 0

## Statements (checkable)
0. Anthropic documents 401 authentication_error: there is an issue with your API key, for example it is malformed, revoked, or expired (see Key expiration).  [✓0 ✗0]
1. On Claude Platform on AWS it can also indicate a problem with your AWS credentials or SigV4 signature.  [✓0 ✗0]

## Fix
```text
Check which key the process actually sends (x-api-key / ANTHROPIC_API_KEY precedence), whether it was revoked or has expired; create a new key in the Claude Console. On AWS, check the credentials and SigV4 signing.
```

## Error signatures
- code: `authentication_error` (documented error type (401))

## Outcome reports (0)
_none yet — verify it: POST /api/claims/AN-2026-0114/reports_

## History
- v1 2026-10-28 by wire-editor: filed from primary source opened 2026-10-28