MarkupConverter converting bullet point from rtf to html

I am using MarkupConverter tool (from github) to convert rtf to html. Whenever i try to convert an rtf that has bullet points, it crashes with the following error.

Unrecognized structure in data format 'Rich Text Format'. Parameter name: stream

It happens in the function ConvertRtfToXaml

textRange.Load(rtfMemoryStream, DataFormats.Rtf);

Complete function code is:

public static string ConvertRtfToHtml(string rtfText)
    {
        var xamlText = string.Format(FlowDocumentFormat, ConvertRtfToXaml(rtfText));

        return HtmlFromXamlConverter.ConvertXamlToHtml(xamlText, false);
    }

private static string ConvertRtfToXaml(string rtfText)
    {
        var richTextBox = new RichTextBox();
        if (string.IsNullOrEmpty(rtfText)) return "";

        var textRange = new TextRange(richTextBox.Document.ContentStart, richTextBox.Document.ContentEnd);

        //Create a MemoryStream of the Rtf content

        using (var rtfMemoryStream = new MemoryStream())
        {
            using (var rtfStreamWriter = new StreamWriter(rtfMemoryStream))
            {
                rtfStreamWriter.Write(rtfText);
                rtfStreamWriter.Flush();
                rtfMemoryStream.Seek(0, SeekOrigin.Begin);

                //Load the MemoryStream into TextRange ranging from start to end of RichTextBox.
                textRange.Load(rtfMemoryStream, DataFormats.Rtf);
            }
        }

        using (var rtfMemoryStream = new MemoryStream())
        {

            textRange = new TextRange(richTextBox.Document.ContentStart, richTextBox.Document.ContentEnd);
            textRange.Save(rtfMemoryStream, DataFormats.Xaml);
            rtfMemoryStream.Seek(0, SeekOrigin.Begin);
            using (var rtfStreamReader = new StreamReader(rtfMemoryStream))
            {
                return rtfStreamReader.ReadToEnd();
            }
        }

    }