Adding a new Customer Object cannot be done on live instance

Develop, Build & Integrate APIs & Integrations
4

Hi @BGrauer,

are you maybe using the https://api.hubapi.com/crm/v3/schemas endpoint and oauth token?
Then you should try to use HubSpot API key. Be careful with this API key - it provides full access to your entire portal!

Any Enterprise account can create, read, and update custom objects using API key authentication.

In the HubSpot Developer Slack, a user also wrote that you should still set the following scopes: crm.schemas.custom.read, crm.objects.custom.read, crm.objects.custom.write

In the Marketplace there is the App “Easy Custom Objects
Create and modify existing custom objects inside your HubSpot portal”, which may also help you.

Hope this helps getting the Custom Objects created.