ajax push data to backend method

I am building a custom webpush notificaiton. I am getting the token that the service worker creates then using ajax to push it to my back end.

My issue is the the response is always 500 and it never reaches a break point. Ideally I want to reach the method that is in my dedicated project not my cms project however below is the code just to get the reponse to the back end in the Old_App_Data.

Thank you!

Relavent code in my javascript webpart.

   .then(function(token){
        $.ajax({
       type: "POST",
       url: "Notfications.aspx/getToken",
       data: token,
       dataType: 'json',
       contentType: "application/json; charset=utf-8",
       success: function (result) {
          alert("Result: "+ result );
       },
       error: function (result) {
            alert("Error try again");
       }
   });

code in my soultion

[assembly: RegisterCustomClass("MyClassName", typeof(getTokenAjax))]
namespace CMSApp.Old_App_Code
{
    public class getTokenAjax
    {
        [WebMethod]
        [ScriptMethod]
        public static string getToken(string webtoken)
        {
            var x = webtoken;
            return webtoken;
        }
    }
}