Parse Rest API PUT not working for Unity WebGL

I am working on unity webgl build on our existing IOS running app. All the data about users are saving on Parse. I have implemented Rest API to communicate with Parse. Implemented Get and Post(without passing the method header) they are working fine but when i am trying to update the data using PUT :

 string url = "https://api.parse.com/1/"
 string ObjectID = "ERd99Q0kmd"
 
 string CallLink = url + "classes/PlayerProfile/" + ObjectID ;
             string jsonString = "{\"TotalCoins\":40}";
 
             WWWForm form = new WWWForm();
             var headers = form.headers;
             headers["X-Parse-Application-Id"] = appID;
             headers["X-Parse-REST-API-Key"] = restapikey;
             headers["Content-Type"] = "application/json";
             headers["Content-Length"] = jsonString.Length.ToString();
 
             var encoding = new System.Text.UTF8Encoding();
 
             WWW www = new WWW(CallLink,encoding.GetBytes(jsonString),headers);
 
             yield return www;
             if (www.error != null)
             {
                 Debug.Log( "CallGet:Error:"+www.error);
             }
             else
             {
                 Debug.Log("CallGet:Success:"+www.text);
             }

It gives Bad Request error. I also tried the header "Method" it also give Bad Request but when i tried "X-HTTP-Method-Override" it works in unity editor but still it doesn't working in Browser and getting following Error :

Request header field X-HTTP-Method-Override is not allowed by Access-Control-Allow-Headers in preflight response.

Please help me out how can i update the data.