Generating an application access token using eBay RESTful APIs Error 401 grant type in request is not supported by authorization server

https://developer.ebay.com/api-docs/static/oauth-client-credentials-grant.html

I am trying to generate an application access token in bubble.io but am getting hit with error 401 grant type in request is not supported by authorization server.

bubble api connector

bubble workflow

bubble workflow

When I preview my page, chrome developer tools displays the following error:


{"error":"unsupported_grant_type","error_description":"grant type in request is not supported by the authorization server"}