Privilege issue while trying to close purchase order through rest api

Summary:

403 - Forbidden error while trying to close the purchase order via Rest API

Content (please ensure you mask any confidential information):

We are trying to close the purchase orders via Rest API, however it gives 403-forbidden error.
Added following role & privileges as well:-
Buyer
procurement manager
Agent - with full access
Close Purchase Order
Procurement REST Service

Manage Purchase Order by Web Service
Procurement integration specialist

However while calling the API

fscmRestApi/resources/11.13.18.05/purchaseOrders/3000000596/action/close

It is flashing error 403-forbidden

Version (include the version you are using, if applicable):

25-D

Code Snippet (add any code snippets that support your topic, if applicable):