Add license checks to Office and SharePoint Add-ins

Created Office Add-ins (App ID 42949681619) Implemented enter link description here.

var decodedToken = getUrlVars()["et"];
var decodedBytes = encodeURIComponent(decodedToken);
var Valid = false;

function getUrlVars() {
    var vars = [], hash;
    var hashes = window.location.href.slice(window.location.href.indexOf('?') + 1).split('&');
    for (var i = 0; i < hashes.length; i++) {
        hash = hashes[i].split('=');
        vars.push(hash[0]);
        vars[hash[0]] = hash[1];
    }
    return vars;
}

function EtokenWeb(sourceWord) {

    try {    
        var xhr = new XMLHttpRequest();    
        var translateRequest = "../Verification.asmx/VerifyEntitlement?et="+ sourceWord;

        xhr.open("POST", translateRequest);
        xhr.responseType = 'document';    
        xhr.onload = function () {
            var result = parseResponse(xhr.responseXML);
            Valid = result;
        }

        // Send the HTTP request.
        xhr.send();
    }
    catch (ex) {
        app.showNotification(ex.name, ex.message);
    }
}

function parseResponse(responseText) {
    var response = "Cannot read response.",
        xmlDoc;

    try {
        response = responseText.getElementsByTagName("string")[0].firstChild.nodeValue;
    }
    catch (ex) {
        app.showNotification(ex.name, ex.message);
    }

    return response;
}

using BenWeb.VerificationService;
using System;
using System.Collections.Generic;
using System.Collections.Specialized;
using System.Linq;
using System.Web;
using System.Web.Services;

namespace BenWeb
{
    [WebService(Namespace = "http://tempuri.org/")]
    [WebServiceBinding(ConformsTo = WsiProfiles.BasicProfile1_1)]
    [System.ComponentModel.ToolboxItem(false)]
    [System.Web.Script.Services.ScriptService]
    public class Verification : System.Web.Services.WebService
    {
        private static VerificationServiceClient service = new VerificationServiceClient();
        VerifyEntitlementTokenRequest request = new VerifyEntitlementTokenRequest();

        [WebMethod]
        public bool VerifyEntitlement ()
        {
            // Store the URL from the incoming request and declare
            // strings to store the query and the translation result.
            string currentURL = HttpContext.Current.Request.RawUrl;
            string queryString;
            bool result = false;

            try
            {
                // Check to make sure some query string variables exist.
                int indexQueryString = currentURL.IndexOf('?');
                if (indexQueryString >= 0)
                {
                    queryString = (indexQueryString < currentURL.Length - 1) ? currentURL.Substring(indexQueryString + 1) : String.Empty;

                    // Parse the query string variables into a NameValueCollection.
                    NameValueCollection queryStringCollection = HttpUtility.ParseQueryString(queryString);

                    string Token = queryStringCollection["et"];
                    if (Token != null)
                    {
                        request.EntitlementToken = Token;
                        VerifyEntitlementTokenResponse omexResponse = service.VerifyEntitlementToken(request);
                        result = omexResponse.IsValid;
                    }
                    else result = false;
                }
            }
            catch (Exception ex)
            {
                //result = ex.Message;
                result = false;
            }

            // to the HTTP request.
            return result;

        }
    }
}

Added in code:

if (Valid)
            {
                $('#highlight-button').click(SelectedRange);
                $('#highlight2-button').click(Recalculation);
            }

Sent for approval. Received a comment "Your add-in does not work as described in your addin description. Nothing happens when we click the “Choose” button."

Test license VerificationService worked fine (IsTest=True, IsValid=False). Where I went wrong? And how to check for this (correct) license?