copper webform failed to create the Copper Lead. Client error: `POST https://api.copper.com/developer_api/v1/leads` resulted in a `403 Forbidden` response: {"success":false,"status":403,"message":"Feature not enabled"}

You have to be sure Leads are enabled.

To do so go Settings -> Open(if not opened) Customize fieldset -> Lead Statuses and click "Enable Leads" there. After that "Leads" link appear in your UI and integration will work.

Automatically closed - issue fixed for 2 weeks with no activity.