WCF - Bool returns Void

Question

Hello, good morning, good morning! When I call the WCF service on the client side, a function that was made to return bool is returning void.. and even asks for more parameters than those indicated within the WCF that would be the Email and Password, since it serves to verify the login.

WCF works perfectly, I’m not really able to unite the customer to the service..

The code below is WCF:

public bool Login(string email, string password)
{
    bool ativo = false;
    try
    {
        if (string.IsNullOrEmpty(email) == false && string.IsNullOrEmpty(password) == false)
        {
            var comando = new SqlCommand();
            comando.Connection = Connection.conexao_DB;
            Connection.Conetar_DB();

            SqlDataAdapter cmd = new SqlDataAdapter("SELECT * FROM login where email = @Email and password = @Password", Connection.conexao_DB);
            cmd.SelectCommand.Parameters.Add(new SqlParameter("@Email", email));
            cmd.SelectCommand.Parameters.Add(new SqlParameter("@Password", password));
            DataTable dt = new DataTable();
            cmd.Fill(dt);

            List<LoginModel> getUser = new List<LoginModel>();
            foreach (DataRow row in dt.Rows)
            {
                LoginModel user = new LoginModel();
                user.Email = row["email"].ToString();
                user.Password = row["password"].ToString();
                if (email == row["email"].ToString() && password == row["password"].ToString())
                {
                    ativo = true;
                };
                getUser.Add(user);
            }
            Connection.Desconetar_DB();
            //return ativo;
        }
    }
    catch (Exception)
    {
        throw new FaultException("ERROR");
    }
    return ativo;
}

Inside the Iservice.Cs:

namespace WcfMarketPlace
{
    [ServiceContract]
    public interface IService
    {
        [OperationContract]
        bool Login(string email, string password);
    }
}
Do lado do cliente:

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web;
using System.Web.UI;
using System.Web.UI.WebControls;
using TESTE.wcfMarketPlace;
namespace TESTE
{
    public partial class Login : System.Web.UI.Page
    {
        protected void Page_Load(object sender, EventArgs e)
        {
            
        }

        public void loginT_Click(object sender, EventArgs e)
        {
            try
            {
                wcfMarketPlace.Service wcf = new wcfMarketPlace.Service();
                bool ativo = false;

                ativo = wcf.Login(loginEmail.Text, loginPassword.Text);
            }
            catch 
            {
                Response.Write("<script>alert('Usuario Incorreto')</script>");
            }
            //wcf.Close();
        }
    }
}

It may be a basic mistake, but I really don’t understand since I’m a beginner, I appreciate any kind of help! :)

Thank you!