Using OAuth Authentication
OAuth requires the authenticating user to interact with eBay using the browser. The connector facilitates this in various ways as described below.
You will need to register an app to obtain the OAuthClientId and OAuthClientSecret.
In the headless OAuth flow, users need to authenticate via a browser on another machine. You will need to create a custom OAuth app.
Creating a Custom OAuth App
See Creating a Custom OAuth App for a procedure.