Web Forms API returns 404 for GET and POST endpoints in Developer Account

I am using a DocuSign Developer (Demo) account and created a Web Form in the same account.

I am able to access and edit the Web Form from the UI using:

https://apps-d.docusign.com/send/forms/edit/{formId}

I am authenticating using JWT OAuth, and the access token is generated successfully.

However, when I try to call the Web Forms API, I consistently receive 404 Not Found.

GET Request

GET https://apps-d.docusign.com/api/webforms/v1.1/accounts/{accountId}/forms/{formId}

POST Request

POST https://apps-d.docusign.com/api/webforms/v1.1/accounts/{accountId}/forms/{formId}/instances

Both requests return 404 Not Found.

I have verified:

• The account ID is correct.
• The form ID is taken from the Web Form edit URL.
• JWT authentication is successful.
• The Web Form was created in the same developer account.

My questions are:

1. Are these the correct Web Forms API endpoints?
2. Is the Web Forms REST API available for all Developer (Demo) accounts?
3. Does the Web Forms API require additional account enablement or OAuth scopes?
4. Is there any documentation showing how to create a Web Form instance programmatically using the REST API?

Any guidance would be appreciated or give the full flow steps about how to preceed