downstream_timeout
HTTP 504 — an FMG platform service behind Connect did not respond in time.
FMG Connect gave up waiting on a platform service it depends on.
Retryable. Retry with exponential backoff and jitter. Because the
original request may have been processed before the timeout, prefer
operations that are safe to repeat, and check state (for example by reading
consent status) before re-sending anything user-visible.
All error codes and the retry model: Errors.