UPSTREAM_UNAVAILABLE

A dependency (chain gateway, node) was unavailable before anything was committed.

HTTP status	503
Group	Relay path
Retryable	Yes — the same request may be sent again
Re-sign	SAME_BYTES — resend the transaction you already have, byte for byte

What happened

The failure happened before the commit point, so no signature was released and nothing was broadcast.

What to do

Retry with the same bytes.

The problem document

Every error is application/problem+json (RFC 9457) with the same shape:

{
  "type": "https://docs.co-relayer.com/errors/upstream-unavailable",
  "title": "A dependency (chain gateway, node) was unavailable before anything was committed.",
  "status": 503,
  "detail": "A sentence about this specific occurrence.",
  "instance": "req_01JB…",
  "code": "UPSTREAM_UNAVAILABLE",
  "retryable": true,
  "resign": "SAME_BYTES",
  "hint": "Retry with the same bytes."
}

See the error model for what each member means and how to handle unknown codes.