LdContextNotAvailable

Andromeda answers 504 with the problem type https://uri.etsi.org/ngsi-ld/errors/LdContextNotAvailable. A remote @context the request names couldn't be fetched. Andromeda acts as a gateway that failed to reach an upstream document, which is why the specification gives this a gateway status rather than 500. The specification defines this type for a context that can't be retrieved and binds it to 504.

When this comes back

• The URL isn't reachable from the broker, or the download takes longer than jsonld.fetch.timeout (10 seconds by default). The broker does the fetching, not your client, so a context your browser can reach may still be out of the broker's reach. See Fetching remote @context documents.
• The document is larger than jsonld.fetch.max_size (2 MiB by default). See Andromeda's own bounds.
• jsonld.fetch.mode is "disabled", and the context isn't one Andromeda stores or still has cached. See Deployment security.
• A subscription or registration names a jsonldContext that can't be fetched. It is fetched when you write the subscription or registration, so a broken URL fails at once, not at the first notification. See Subscriptions.

Store the context in the broker instead, as the Quickstart does, and there is nothing left to fetch.

A context chain that loops, or runs deeper than eight documents, isn't this error. Andromeda refuses it with BadRequestData before fetching anything. See What gets refused.