if I set a breakpoint on this method and go to localhost:1234/api/employee, the breakpoint will be hit. If I try to do localhost:1234/api/employee/SOME_ID it'll 404. What am I overlooking here?

EmployeeController.cs

using System;
using System.Collections.Generic;
using System.Linq;
using System.Threading.Tasks;
using System.Web.Http;
using MyApp.ElasticData;
using MyApp.Models;

namespace MyApp.Controllers
{
    public class EmployeeController : BaseController
    {
        [Route("api/employee")]
        [HttpGet]
        public async Task<Employee> GetByPernr(string id = null)
        {
            var app = new ElasticEvents();
            var emp = await app.GetElasticDataById(id);
            var empData = new Employee
            {
                FirstName = emp.FirstName,
                LastName = emp.LastName,
                NtId = emp.NtId
            };

            return empData;
        }
    }
}

Global.asax.cs

public static void RegisterRoutes(RouteCollection routes)
{
    routes.IgnoreRoute("{resource}.axd/{*pathInfo}");
    routes.LowercaseUrls = true;

    routes.MapRoute(
        "Default", // Route name
        "{controller}/{action}/{id}", // URL with parameters
        new { controller = "Home", action = "Index", id = UrlParameter.Optional } // Parameter defaults
    );

}