How to create multiple records using Rest API in single payload for Custom Object?

Summary:

We have created a custom object and we are trying to create multiple records using the Rest API. We have checked this document "REST API Batch Processing To Create Multiple Records on Standard Objects (Doc ID 2215960.1) ", but this is not working for our custom object which we created.

Can you please help us.

We tried by creating for standard objects it was showing the following error.

This is the body we have given

{

    "parts": [

        {

            "id": "part1",

            "path": "/latest/accounts",

            "operation": "create",

            "payload": {

                "OrganizationName": "BulkAccount2"

            }

        },

        {

            "id": "part2",

            "path": "/latest/accounts",

            "operation": "create",

            "payload": {

                "OrganizationName": "AccountBulk1"

            }

        }

    ]

}