Jira API请求错误

我正在尝试连接jira与api。我已经有问题了，但现在我想制造问题，但没用。我得到了错误:Badrequest。所以我尝试了很多东西，甚至什么都不发，但它不起作用。它仍然给出相同的错误

那么设置中有什么东西阻止了我的帖子吗?

代码:

    var webAddr = "https://<username>.atlassian.net/rest/api/2/issue/";
    var httpWebRequest = (HttpWebRequest)WebRequest.Create(webAddr);
    httpWebRequest.ContentType = "application/json; charset=utf-8";
    httpWebRequest.Method = "POST";            
    using (var streamWriter = new StreamWriter(httpWebRequest.GetRequestStream()))
    {
        string json = "{}";
        streamWriter.Write(json);
        streamWriter.Flush();
    }
    var httpResponse = (HttpWebResponse)httpWebRequest.GetResponse();
    using (var streamReader = new StreamReader(httpResponse.GetResponseStream()))
    {
        var result = streamReader.ReadToEnd();
        return result;
    }