gistfile1.txt

string type = "test";

string data = @"{""fields"":{""project"":{""key"": ""MD""},""summary"": 
""Support EXAMPLE"",""description"": ""Testing Support"",""issuetype"":  
{""name"": "+ type +" }}}";

string postUrl = "https://aconline.atlassian.net/rest/api/2/issue";
byte[] cred = UTF8Encoding.UTF8.GetBytes("username:password");
HttpClient client = new HttpClient
{
    DefaultRequestHeaders = 
    {
        Authorization = new AuthenticationHeaderValue("Basic", Convert.ToBase64String(cred)),
        Accept = { new MediaTypeWithQualityHeaderValue("application/json") }
    },
    BaseAddress = new Uri(postUrl)
};

HttpContent content = new StringContent(data, Encoding.UTF8, "application/json");
HttpResponseMessage response = client.PostAsync("issue", content).Result;

if (response.IsSuccessStatusCode)
{                   
    ViewData["Result"] = "Success! your issue has been posted.";
}
else
{                  
    ViewData["Result"] = response.Content.ReadAsStringAsync().Result;
}