`upstream_error`

502 Bad Gateway A service this request depends on failed.

When you get it

A service this request depends on failed. It is always answered with HTTP 502 - one code means one status, so a client may key its handling on either.

Fields it carries

Inside each errors[] entry, beside pointer:

service: The dependency that failed or is unavailable.
retryAfter: How long to wait before retrying, in seconds. Mirrors the Retry-After header.
origin: Which delivery path handled the attempt (for example `core`, `api2-fallback`).
outcome: How the delivery or test attempt ended, as the pipeline reported it.
notificationId: The id of the notification record this attempt created - quote it in a support request about a delivery.
externalId: The id the downstream channel (webhook endpoint, SMS gateway, provider) assigned to this delivery attempt, when it returned one.
error: The downstream failure message, when the dependency that was called returned one.

A field is omitted when the server genuinely does not know it - an absent member is never the same as an empty one.

How to fix it

A dependency of this request failed. It is not fixable client-side; retry later.

Shape

{
  "type":   "https://api2.host-tracker.com/problems/upstream-error",
  "title":  "A service this request depends on failed.",
  "status": 502,
  "code":   "upstream_error",
  "errors": [
    { "service": …, "retryAfter": …, "origin": …, "outcome": …, "notificationId": …, "externalId": …, "error": … }
  ]
}