> ## Documentation Index
> Fetch the complete documentation index at: https://docs.permitcore.io/llms.txt
> Use this file to discover all available pages before exploring further.

# Invalid target_segment

> 422 — An unknown `target_segment` value was supplied.

An unknown `target_segment` value was supplied.

```json 422 application/problem+json theme={null}
{
  "type": "https://docs.permitcore.io/errors/invalid-target-segment",
  "title": "Invalid target_segment",
  "status": 422,
  "detail": "…",
  "instance": "/v1/permits/target",
  "request_id": "req_1f07fb45782b445e9f6312ba23921234"
}
```

Every PermitCore error is [RFC 9457](https://www.rfc-editor.org/rfc/rfc9457)
`application/problem+json`. **Branch on `type` (a stable URI)**, not on `title`
or `detail` (human-readable, may change).

## When it occurs

One or more `target_segment` values are not in the canonical segment enum. The response `detail` enumerates the full accepted whitelist.

## How to fix

Use one of the canonical segment slugs (see [Cohorts](/concepts/cohorts)). `target_segment` accepts a comma-separated list; every value must be valid.

**Not retryable** — fix the request before resubmitting; retrying unchanged returns the same error.

See the full [error catalog](/errors) for the response shape and retry matrix.
Every response carries an `x-request-id` header — include it in any support request.