Create Purchase Receipt from REST API - acumatica

Question

I'm trying to use the new OpenAPI 2.0 setup in Acumatia 21R1 to create a PO Receipt. I've tested creating several other types of records (eg: StockItems) and virtually the same code works perfectly. This instance of Acumatica has several tenants but no branches.
I've also used this same code put pointed it to an instance of Acumatica that has one tenant and multiple branches, and as long as I set the branch it works fine.
When I run it I get "curyid can not be null". This leads me to believe that somehow it's not figuring out the branch or tenant correctly, but if I use the same login code I can pull data from those tenants just fine. I've also tried passing the json directly and including the curyid set to USD, but that has the same effect.
Any thoughts on what I am doing wrong?
private createPOR()
{
string baseURL = "https://acumatica.[good url goes here].com/AcumaticaPWS";
string strLogin = baseURL + "/entity/auth/login";
var client = new RestClient(strLogin);
var request = new RestRequest(Method.POST);
request.AddHeader("Accept", "application/json");
request.AddHeader("Content-Type", "application/json");
string strBody = "{ \"name\": \"admin\", \"password\": \"[proper password]\", \"tenant\": \"PWS Milwaukee\", \"branch\": \"\"}";
request.AddJsonBody(strBody);
IRestResponse response = client.Execute(request);
txtResults.Text = response.Cookies.SingleOrDefault(x => x.Name == ".ASPXAUTH").Value.ToString();
RestResponseCookie sessionCookie = response.Cookies.SingleOrDefault(x => x.Name == ".ASPXAUTH");
// Create the new one for send the data.
string strItems = baseURL + "/entity/Default/20.200.001/PurchaseReceipt";
client = new RestClient(strItems);
request = new RestRequest(Method.PUT);
request.AddCookie(sessionCookie.Name, sessionCookie.Value);
request.AddHeader("Accept", "application/json");
request.AddHeader("Content-Type", "application/json");
PurchaseReceipt theRec = new PurchaseReceipt{ Type = new StringValue { Value = "Receipt" },
VendorID = new StringValue { Value = "V1002" }
};
// BaseCurrencyID = new StringValue { Value = "USD" },
// CurrencyID = new StringValue { Value = "USD" }
request.AddJsonBody(JsonConvert.SerializeObject(theRec));
response = client.Execute(request);
txtResults.Text += Environment.NewLine + "Response" + response.StatusCode.ToString();
// Setup to log out.
string strLogout = baseURL + "/entity/auth/logout";
client = new RestClient(strLogout);
request = new RestRequest(Method.POST);
request.AddHeader("Accept", "application/json");
request.AddHeader("Content-Type", "application/json");
response = client.Execute(request);
txtResults.Text += Environment.NewLine + response.StatusCode.ToString();
}

Answer 1

Like Samvel mentioned in the comments this issue is usually the result of not having provided the Branch during the login.
But once the Branch has been provided it still needs to be provided as a cookie for the other request down the line.
That cookie should have the name "UserBranch" with its value being an integer that should be returned from the login request.