invalid_idempotency_key

The Idempotency-Key (or `transaction-id` header) is longer than 255 characters or holds non-printable characters. Nothing was changed.

HTTP 400. Nothing reached the broker.

Likely cause: A key built from long ids, or one carrying control characters, tabs or bidi marks.

What to do: Send 1 to 255 printable characters. Keys are never truncated, so two long keys can’t collide.

Retry: No. The same request gets the same answer; change something first.

Listed under Orders and idempotency in Errors. Send the error’s requestId to support and we can find the request.