In Web API : No action found on Account controller

Question

I have create web api project and getting error like

<Error>
<Message>No HTTP resource was found that matches the request URI 'https://localhost:44370/Account/validlogin?userName=admin?userPassword=admin'.</Message>
<MessageDetail>No action was found on the controller 'Account' that matches the request.</MessageDetail>
</Error>

Here is my Controller code

using System;
using System.Collections.Generic;
using System.Linq;
using System.Net;
using System.Net.Http;
using System.Web.Http;

namespace WebAPI.Controllers
{
    public class AccountController : ApiController
    {

        [HttpGet]

        public HttpResponseMessage ValidLogin(string userName, string userPassword)
        {
            if (userName == "admin" && userPassword == "admin")
            {
                return Request.CreateResponse(HttpStatusCode.OK, value: TokenManager.GenerateToken(userName));
            }
            else
            {
                return Request.CreateErrorResponse(HttpStatusCode.BadGateway, message: "User name and password is invalid");
            }
        }

        //public string get()
        //{
        //    return "value";
        //}
    }
}

And WebApiConfig.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Web.Http;

namespace WebAPI
{
    public static class WebApiConfig
    {
        public static void Register(HttpConfiguration config)
        {
            // Web API configuration and services

            // Web API routes
            config.MapHttpAttributeRoutes();

            config.Routes.MapHttpRoute(
                name: "DefaultApi",
                routeTemplate: "{controller}/{action}/{id}",
                defaults: new { id = RouteParameter.Optional }
            );
        }
    }
}

Now I have run project and pass url like

 

https://localhost:44370/Account/validlogin?userName=admin?userPassword=admin

 

and getting error like

<Error>
<Message>No HTTP resource was found that matches the request URI 'https://localhost:44370/Account/validlogin?userName=admin?userPassword=admin'.</Message>
<MessageDetail>No action was found on the controller 'Account' that matches the request.</MessageDetail>
</Error>

Please give me some suggestion I have tried all like change action name , api route etc.. but not found any solution.