%使用Tweetsharp在Twitter帖子中签名会导致401未经授权

我有一段简单的代码，可以发送一条Tweet。保留带有%符号的消息会导致401未经授权的错误：

class Program
{
    static void Main(string[] args)
    {
        var test = new TwitterService("ConsumerKey", "ConsumerSecret", "Token", "TokenSecret");
        try
        {
            // "Test 1, So, I know there's no #inflation and so on...but the 10y inflation swap just went to 2.80%. 5y CPI 5y forward is 3.15%. Hmmm."
            test.SendTweet(WebUtility.HtmlEncode("Test 3, So, I know there's no #inflation and so on...but the 10y inflation swap just went to 2.80%. 5y CPI 5y forward is 3.15. Hmmm."));
        }
        catch (Exception ex)
        {
            if (ex.Message.Equals(""))
            {
            }
        }
    }
}

如果我通过TweetDeck或直接使用Twitter页面发送相同的消息，它会毫无问题地发布。有什么想法吗？