I have been able to connect/authenticate to Dataverse with Postman by following the steps in this guide: https://docs.microsoft.com/en-us/power-apps/developer/data-platform/webapi/setup-postman-environment
I have tried using the Dynamics 365 web service for this connection, but could not get it to work. I am trying to create a new web service in FME Desktop that uses the OAuth 2.0 implicit grant type to retrieve at token, as in the steps from the linked guide, but have been unsuccessful at this as well; when I try to authenticate or create a new web connection from the web service, I am unable to get the browser window/sign in prompt to appear and allow me to enter my account credentials.
I am attempting to create this web service as a new Token Service, rather than a new OAuth 2.0 Service, as the parameters for this type of service seem to be what I need to enter/what I am doing with Postman.