Setting up ERPNext as oauth2 provider

The message returned by oauth2 client suggests

  1. Frappe Server URL is missing.
  2. oauth2 client assumes that you’ve access_token and proceeds with the request resulting into missing access token

The guide about setting up IDP is for a scenario where both IDP and Client App are two separate frappe servers.

In your case the Client App is not a frappe server. So only Frappe Server you’ve setup must have Frappe Server URL setup. No need for Client Secret and Client ID

Example for Frappe Server URL setup for IDP/Primary frappe server
erp.mntechnique.com is the Frappe IDP and the main Frappe Server with ID related resource.

same server hosts the OAuth Clients.

rauth is python oauth client library used in Frappe. Example for using rauth

The same thread has more gui friendly postman example