Bad Address

When I make HTML TO PDF API using  .Net SDK I get this error 

"{"Bad Address, request terminated; requestId=8a16cea5-deb2-4d6b-a044-74b4e0451467"}"

private async Task<Stream> CreateFromHtmlStream(Stream htmlDataStream)
{
    try
    {
        // Initial setup, create credentials instance
        var credentials = GetCredentials();

        // Creates a PDF Services instance
        var pdfServices = new PDFServices(credentials);

        // Creates an asset(s) from source file(s) and upload
        var asset = pdfServices.Upload(htmlDataStream, PDFServicesMediaType.HTML.GetMIMETypeValue());

        // Create parameters for the job
        var htmlToPDFParams = GetHtmlToPdfParams();

        // Creates a new job instance
        var htmlToPdfJob = new HTMLToPDFJob(asset).SetParams(htmlToPDFParams);

        // Submits the job and gets the job result
        var location = pdfServices.Submit(htmlToPdfJob);
        var pdfServicesResponse = pdfServices.GetJobResult<HTMLToPDFResult>(location, typeof(HTMLToPDFResult));

        // Get content from the resulting asset(s)
        var resultAsset = pdfServicesResponse.Result.Asset;
        var streamAsset = pdfServices.GetContent(resultAsset);

        // Save the PDF to a temporary file
        var tempPdfFilePath = Path.GetTempFileName();

        using (var tempPdfStream = new FileStream(tempPdfFilePath, FileMode.Create, FileAccess.Write))
        {
            streamAsset.Stream.CopyTo(tempPdfStream);
        }

        // Convert the PDF to Word
        var outputStream = ConvertPdfToWordStream(tempPdfFilePath);

        // Clean up temporary PDF file
        System.IO.File.Delete(tempPdfFilePath);

        return outputStream;
    }
    catch (ServiceUsageException ex)
    {
        //_logger??.LogError("Exception encountered while executing operation", ex);
    }
    catch (ServiceApiException ex)
    {
        //_logger??.LogError("Exception encountered while executing operation", ex);
    }
    catch (SDKException ex)
    {
        //_logger??.LogError("Exception encountered while executing operation", ex);
    }
    catch (IOException ex)
    {
        //_logger??.LogError("Exception encountered while executing operation", ex);
    }
    catch (Exception ex)
    {
        //_logger??.LogError("Exception encountered while executing operation", ex);
    }

    return null;
}

My API code is copied above. I am clueless to find what is going on here. I am trying to send HTML to our RESTful POST endpoint & perform this operation. 

Please help me asap because we are evaluvating this service to buy coporate licence.