[Guardian support-frontend error-handling docs]: In practice the list rarely contains more than one item. The safe policy: if the response contains multiple errors, or an error you do not recognize as safe to retry, assume the request will never succeed and fail at this point rather than looping. Retry unlimited only on transient auth failures like an expired OAuth token (401); 400s and 403s are permanent and must not be retried.

Context: Zuora API failures return a list of errors, which makes retry logic tricky: a mix of fatal and non-fatal errors in one response.

## Matched source
Source: Source: https://github.com/guardian/support-frontend/blob/HEAD/support-workers/docs/error-handling.md
Original query: "Zuora API errors arrive as a list - retry only the safe ones"
Key terms: arrive, errors, list, ones, only, retry, safe, zuora