Consuming the BTP CF MyInbox API

Hello Everyone,
I'm trying to get the substitution rule by consuming the following SAP Business HUB API: https://api.sap.com/api/SAP_CP_Workflow_TCM_CF/resource

I tried the following way:

I tried to consume it from ui5 application

Steps followed:

1. Create a destination in BTP for the workflow endpoint and used Oauth2tokenExchange based authentication

   

2. From Ui5 Application I called the destination and calling substitute API endpoint.

PFA, Controller.js

xs-app.json

I'm getting unauthorized error, when I'm trying to hit this Api endpoint:

(I already assigned the workflowParticipant role to me)

Please help in fixing the issue, your feedback is appreciated
thanks