# E05006 — TrackingDomainRequired

Configure a tracking domain before enabling click and open tracking.

- **HTTP status**: `409`
- **Type**: `conflict_error`
- **Name**: `TrackingDomainRequired`

## What to do

Configure a tracking domain on the sending domain, then retry.

Operations that resolve this:

- [Update a sending domain](/docs/api/reference/update-domain)

## Related

- [Idempotency](/docs/api/idempotency): safe retries and key reuse rules
- [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`