# E05018 — InboundDomainAlreadyClaimed

This domain is already receiving inbound mail for another organization. Choose a different subdomain, or contact support if you believe this is an error.

- **HTTP status**: `422`
- **Type**: `validation_error`
- **Name**: `InboundDomainAlreadyClaimed`

## What to do

The request body parsed, but one or more values are invalid. Follow the message above; when you contact support, quote the response's `request_id` so the team can locate the request.

## Related

- [E05xxx — Domains & DNS](/docs/api/errors/E05xxx): every code in this range
- [Errors](/docs/api/errors): the full wire contract, status mapping, and error catalog
- [Error handling](/docs/guides/errors): branching on `type` and `code`, validation details, and `vendor_code`