Can you send your headers? Are you setting Content Type: application/json? Deals also requires access to the CRM; does the portal you’re trying to create a deal in have access to the CRM?
That endpoint is intended for pulling a deal record (GET) or updating an existing deal record (PUT). If you’re looking to create a new deal record, you should send a POST request to: https://api.hubapi.com/deals/v1/deal/:id
Creating a deal using the Create a Deal endpoint should return a 200 response code and the deal details. Can you give me some info on the request you’re making and the response you’re seeing?
POST /deals/v1/deal/ - For a given portal, create a deal. This is particularly useful if you're integrating with a CRM or another application that has a similar notion of a deal. Note that you can create associations between Deals and Contacts and...