OrderAcknowledgement SubmitFeed() in sandbox environment does not work.

[ArneWDev]

Hey,

I've made a unit-test for sandbox environment where I fetch orders and orderItems from Amazon. I then create a XML to send an orderAcknowledgement submit feed. However here I receive the following error:

Message: 
Test method Nayan.Interface.Amazon.Business.Integrationtests.AmazonSellerApi.AmazonApiTests.Test threw exception:
FikaAmazonAPI.AmazonSpApiSDK.Models.Exceptions.AmazonException: Amazon Api didn't respond with Okay, see exception for more details

Sadly, there is no exception with more details provided.

I will drop the code below without sharing sensitive data. If anyone has similar issues, please let me know how to resolve them.
I for one believe i'm missing something in the XML constructed so that Amazon knows this is a sandbox orderAcknowledgement, but your guess is as good as mine.

Thanks in advance. If more information is required please do not hesitate to ask.

        _amazonConnection = new AmazonConnection(new AmazonCredential()
        {
            AccessKey = "YourKey",
            SecretKey = "YourSecretKey",
            RoleArn = "YourRoleArn",
            ClientId = "YourClientId",
            ClientSecret = "YourClientSecret",
            RefreshToken = "YourRefreshToken",
            MarketPlaceID = "YourMarketPlace",
            Environment = Environments.Sandbox,
            IsDebugMode = true,
            SellerID = "YourSellerId"

        });

        ParameterOrderList sandboxParameters = new()
        {
            TestCase = TestCase200
        };

        var orders = _amazonConnection.Orders.GetOrders(sandboxParameters);

        ParameterGetOrder parameterGetOrder = new()
        {
            TestCase = TestCase200
        };

        var orderItems = _amazonConnection.Orders.GetOrderItems(parameterGetOrder.TestCase);

    var orderAcknowledgementItems = new List<OrderAcknowledgementItem>();

        foreach (var orderItem in orderItems)
        {
            orderAcknowledgementItems.Add(new OrderAcknowledgementItem()
            {
                AmazonOrderItemCode = orderItem.OrderItemId,
                MerchantOrderItemID = "our orderItem reference"
            });
        }

        ConstructFeedService createDocument = new ConstructFeedService("A2YQFYAETBR5O7", "1.01");
        var list = new List<OrderAcknowledgementMessage>();
        list.Add(new OrderAcknowledgementMessage()
        {
            AmazonOrderID = orders[0].AmazonOrderId,
            MerchantOrderID = "our order reference",
            StatusCode = OrderAcknowledgementStatusCode.Success,
            Item = orderAcknowledgementItems
        });
        createDocument.AddOrderAcknowledgementMessage(list);
        var xml = createDocument.GetXML();
        var result = _amazonConnection.Feed.SubmitFeed(xml, FeedType.POST_ORDER_ACKNOWLEDGEMENT_DATA);

		result.Should().NotBeNullOrEmpty();