User can submit charges from WO UI but not using REST API

Summary:

User can submit charges from WO UI but not using REST API

Content (please ensure you mask any confidential information):

User with Job Role "Customer Service Representative" is able to access Work Order details and can press Charges button to create a debrief data and submit the debrief details entered in the Charges page. The same user when trying to create/access debrief via REST API is getting 403 Forbidden error.
Since the user is able to enter debrief via WO UI screen and not via REST API (Postman).

User is not having Field Service Technician Role but without this role, from WO UI, debrief can be created. So what is the restriction from REST API Services.