Can not create "Create Inventory Reservations" Rest Service

Summary

Create Inventory Reservations web service issue

Content

Can not create "Create Inventory Reservations" Rest Service

Hello everyone,

I need to add Oracle Create Inventory Reservations web service to my Oracle Visual Builder app.
Oracle Docs Link: https://docs.oracle.com/en/cloud/saas/supply-chain-management/20a/fasrp/op-fscmrestapi-resources-11.13.18.05-inventoryreservations-post.html

First I tried to add as another endpoint because I've already has one server connection for Inventory Organizations. When I add my endpoint with the body, Visual Builder gave error.
Both body and error messages are in the below.

Body:
{
    "InventoryItemId":100000000569717,
    "OrganizationId":300000001979679,
    "DemandSourceType": "User Defined",
    "DemandSourceName":"WO100201",
    "SupplySourceType":"On hand",