# dry_run_unsupported

> This operation cannot preview its effect; `dryRun` is only accepted where the reference says so.

**Dry run not supported** · HTTP 400

## What it means

This operation cannot preview its effect; `dryRun` is only accepted where the reference says so.

## What to do

Drop `dryRun`, or read first and decide before writing.

## Example

```json
{
  "type": "https://api.bymundi.com/problems/dry_run_unsupported",
  "title": "Dry run not supported",
  "status": 400,
  "detail": "This operation cannot preview its effect; `dryRun` is only accepted where the reference says so.",
  "code": "dry_run_unsupported",
  "requestId": "req_…"
}
```

How to read any error: [Errors guide](https://api.bymundi.com/docs/guides/errors.md).