# upstream_unavailable

> A Tickwire service is unreachable; the request was not sent.

Source: https://tickwire.io/docs/errors/upstream_unavailable/

HTTP 502. Nothing reached the broker.

**Likely cause:** The service is restarting.

**What to do:** Retry after Retry-After.

**Retry:** Yes. Nothing happened (or it was a read), so repeat it, after `Retry-After` when present.

Listed under [Outages and timeouts](https://tickwire.io/docs/errors/#outages-and-timeouts) in [Errors](https://tickwire.io/docs/errors/). Send the error's `requestId` to support and we can find the request.