Can not find element - PLEASE HELP

Hi All,
I have this code

using Microsoft.VisualStudio.TestTools.UnitTesting;
using OpenQA.Selenium;
using OpenQA.Selenium.Appium;
using OpenQA.Selenium.Appium.Windows;
using OpenQA.Selenium.Support.UI;
using System;
using System.Threading;
using System.Threading.Tasks;

namespace IPTV_TEST
{
[TestClass]
public class IPTV1
{
static WindowsDriver Session;
// WebDriverWait wait = new WebDriverWait(Session, TimeSpan.FromSeconds(10));

    [ClassInitialize]

    public static void IPTVLogin(TestContext testContext)
    {
        AppiumOptions apiumOptions = new AppiumOptions();
        apiumOptions.AddAdditionalCapability("app", @"C:\Users\renata.cikova\Desktop\IPTVManagement\Colosseo.IPTVManagement.exe");
        Session = new WindowsDriver<WindowsElement>(new Uri("http://127.0.0.1:4723/"), apiumOptions);
        Session.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(20);

    }
    [TestMethod]
    public void UnsucessLogin()
    {
        Session.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(10);
       var okno= Session.FindElementByClassName("Window");
        Session.Manage().Timeouts().ImplicitWait = TimeSpan.FromSeconds(10);
      //  Session.FindElementByClassName("Button");

        //Thread.Sleep(1000);
        //Session.FindElementByClassName("Button").Click();


    }
}

}
From this selector:






ERROR:
Test method IPTV_TEST.IPTV1.UnsucessLogin threw exception:
OpenQA.Selenium.WebDriverException: An element could not be located on the page using the given search parameters.
Stack Trace:
RemoteWebDriver.UnpackAndThrowOnError(Response errorResponse)
RemoteWebDriver.Execute(String driverCommandToExecute, Dictionary2 parameters) AppiumDriver1.Execute(String driverCommandToExecute, Dictionary2 parameters) RemoteWebDriver.FindElement(String mechanism, String value) AppiumDriver1.FindElementByClassName(String className)
IPTV1.UnsucessLogin() line 35

I really dont know what i do.

Could you help me?

THX
REnata
I will to click on login button, but I get the same ERROR