Error code 500 when trying to add queueitem via orchestrator API

I am trying to add queue item using the orchestrator.
The authentication is successful.
When I dont pass the “data”, I get the “parameter is null” error.
When i send the data, i get the response 500.
I tried different combinations of data, still same error.
Any help appreciated.

Below is the data that I am sending:

            data: 
                            {
                                "itemData": {
                                    "Name": queuename,
                                    "Priority": priority,
                                    "SpecificContent": '{"RequestType":"RefundStatus", "AccountNumber":"' + accountNumber + '"}',
                                    "DeferDate": null,
                                    "DueDate": null,
                                    "Reference": "string"
                                }
                            }

Version I am using is 2018.2.3

I am stuck on the same issue. We are on 2018.1.3 and swagger documentation seems completely wrong. odata/queueitems refers to QueueDefinition docs. If you add the content-type in the header, you’ll see the following error. Can someone please share a working example of json header and body to add a queueitem in 2018.1.3? @badita

{
“message”: “uiQueueDef is null!”,
“errorCode”: 0,
“resourceIds”: null
}

Just in case someone else still has the same problem, it’s possible to add items to a Queue by using the endpoint POST ​/odata​/Queues​/UiPathODataSvc.AddQueueItem.
The body of the request looks like the following:

{
  "itemData": {
    "Name": "Invoices",
    "SpecificContent": {
      "Amount": 1234,
      "CompanyName": "ABC"
    }
  }
}

It’s possible to add more fields, like Priority and RiskSlaDate, but they might not be available in older Orchestrator versions.
More details about this endpoint can be found at Orchestrator’s Swagger page, which can be accessed according to the instructions at API References.
Related post in case of Automation Cloud: How to add QueueItem using Cloud Orchestrator API