Check these screenshots:
Configure the External Application
In Postman the URL will be https://cloud.uipath.com/identity_/connect/token
with the method POST
In Headers specify Content-Type: application/x-www-form-urlencoded
Example:
In the Body select x-www-form-urlencoded
This is a back-end example for the HTTP Request:
POST /identity_/connect/token HTTP/1.1
Host: cloud.uipath.com
Content-Type: application/x-www-form-urlencoded
grant_type=client_credentials&client_id=YOUR_CLIENT_ID&scope=OR.Administration%20OR.Analytics%20OR.Assets%20OR.Audit%20OR.BackgroundTasks%20OR.Execution%20OR.Folders%20OR.Hypervisor%20OR.Jobs%20OR.License%20OR.Machines%20OR.ML%20OR.Monitoring%20OR.Queues%20OR.Robots%20OR.Settings%20OR.Tasks%20OR.TestDataQueues%20OR.TestSets%20OR.Users%20OR.Webhooks&client_secret=YOUR_CLIENT_SECRET
Let us know if this approach worked for you in Postman at least.