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unknown_expand

422 Unprocessable Content   The request asked to expand a value this endpoint does not offer.

When you get it

The request asked to expand a value this endpoint does not offer. It is always answered with HTTP 422 - one code means one status, so a client may key its handling on either.

Fields it carries

Inside each errors[] entry, beside pointer:

parameter

The query parameter the failure is about - the query-side twin of `pointer`.

value

The value the request sent, echoed back so the caller can see what was read.

allowed

The complete set of values this field accepts. Send one of these.

didYouMean

The registered name closest to the one you sent - usually the fix is this spelling.

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

The request was well-formed but a value is not acceptable. The fields above name the offending value and what would be accepted - fix the request and retry.

Shape

{
  "type":   "https://api2.host-tracker.com/problems/unknown-expand",
  "title":  "The request asked to expand a value this endpoint does not offer.",
  "status": 422,
  "code":   "unknown_expand",
  "errors": [
    { "parameter": …, "value": …, "allowed": …, "didYouMean": … }
  ]
}