Kraken API : EAPI:Invalid nonce in c# - asp.net

Question

I am trying to add order in Kraken through API call https://api.kraken.com/0/private/AddOrder. I found EAPI:Invalid nonce error on inserting new order in Kraken. Right Now I am inserting only one order at a time on button click, But there may be the situation when multiple order will be inserted. I have tried too many different solutions to generate a nonce But, still found the same issue. Does anybody know what's wrong?
private JsonObject QueryPrivate(string a_sMethod, string props = null)
{
// generate a 64 bit nonce using a timestamp at tick resolution
Int64 nonce = DateTime.Now.Ticks;
props = "nonce=" + nonce + props;
string path = string.Format("/{0}/private/{1}", _version, a_sMethod);
string address = _url + path;
HttpWebRequest webRequest = (HttpWebRequest)WebRequest.Create(address);
webRequest.ContentType = "application/x-www-form-urlencoded";
webRequest.Method = "POST";
webRequest.Headers.Add("API-Key", _key);
byte[] base64DecodedSecred = Convert.FromBase64String(_secret);
var np = nonce + Convert.ToChar(0) + props;
var pathBytes = Encoding.UTF8.GetBytes(path);
var hash256Bytes = sha256_hash(np);
var z = new byte[pathBytes.Count() + hash256Bytes.Count()];
pathBytes.CopyTo(z, 0);
hash256Bytes.CopyTo(z, pathBytes.Count());
var signature = getHash(base64DecodedSecred, z);
webRequest.Headers.Add("API-Sign", Convert.ToBase64String(signature));
if (props != null)
{
using (var writer = new StreamWriter(webRequest.GetRequestStream()))
{
writer.Write(props);
}
}
//Make the request
try
{
//Wait for RateGate
_rateGate.WaitToProceed();
using (WebResponse webResponse = webRequest.GetResponse())
{
using (Stream str = webResponse.GetResponseStream())
{
using (StreamReader sr = new StreamReader(str))
{
string data = sr.ReadToEnd();
dynamic d = JObject.Parse(data);
return (JsonObject)JsonConvert.Import(data);
}
}
}
}
catch (WebException wex)
{
using (HttpWebResponse response = (HttpWebResponse)wex.Response)
{
using (Stream str = response.GetResponseStream())
{
using (StreamReader sr = new StreamReader(str))
{
string data = sr.ReadToEnd();
if (response.StatusCode != HttpStatusCode.InternalServerError)
{
throw;
}
return (JsonObject)JsonConvert.Import(sr);
}
}
}
}
}

Answer 1

Some exchange platforms allow the use of float type nonce, in your case as you are using Kraken and according to Kraken Api documentation,
nonce = always increasing unsigned 64 bit integer
Kraken will require an integer nonce.
Why invalid nonce ?
In my opinion, the issue occurs when you sent more than one request with the same nonce ...
When you convert the timestamp to an integer, you will will be allowed consequently to sent only 1 request per second (because the limitation relative to the integer nonce changing each second)
In order to have the capability to send more than one requests per seconds, one tips could be to multiply timestamp by 1000 then convert to integer and use this value as nonce.
nonce=integer(1000*timestamp)
In that case you may sent more than 1 request per second (because each nonce will be different) but remember that :
exchange platform have safeguards in place to protect against
abuse/DoS attacks.