Can't get a Simple Rest Post Request to work in ReadAPI that works in Postman

Sorry if this is a novice question, but in Postman, I have POST selected, an endpoint and a body in x-www-form-urlencoded format with some client_id/secret type fields.  No parameters of any kind.  Executing the request works fine.

I can't get the same to work in ReadyAPI.  No matter what I try, I end up with "unsupported request format" error code 135.  I even tried to export the postman request and import it into ReadyAPI.  ReadyAPI converts my body data to header parameters which I don't think is correct.  I'm not sure how to troubleshoot this or what the 2 tools are doing different behind the scenes.

Appreciate any feedback!