Web API Route not working properly in ASP.NET MVC - asp.net-mvc-4

Question

This may be simple and its wierd and I cannot find out the reason why its hapenning.
I am using ASP.NET WEB API 2 Controller: I have a TransactionController, which suddenly stopped working after some modification in one of its action methods. I returned the code back, but its not working anymore.
All the other controllers are working normally. So, I decided two test it by creating two new controllers:
ValueController:
public class ValueController : ApiController
{
public List<string> GetValues()
{
return new List<string>() { "1", "2"};
}
public List<string> GetValues (int ID)
{
return new List<string>() { "1", "2" };
}
public List<string> GetValues(int UserID, DateTime CreateDate)
{
return new List<string>() { "1", "2" };
}
}
TransactionController:
public class TransactionController : ApiController
{
public List<string> GetTransaction(int ID)
{
return new List<string>() { "1", "2" };
}
}
This my webApiConfig
public static void Register(HttpConfiguration config)
{
config.EnableCors();
config.Routes.MapHttpRoute(
name: "DefaultApi",
routeTemplate: "api/{controller}/{id}",
defaults: new { id = RouteParameter.Optional }
);
}
Global.asax
protected void Application_Start()
{
AreaRegistration.RegisterAllAreas();
WebApiConfig.Register(GlobalConfiguration.Configuration);
FilterConfig.RegisterGlobalFilters(GlobalFilters.Filters);
RouteConfig.RegisterRoutes(RouteTable.Routes);
BundleConfig.RegisterBundles(BundleTable.Bundles);
}
When requesting the item controller by the url:
http://localhost:1607/api/value?ID=1, its hitting the GetValues(int ID) action
and the other actions are working fine.
But, the problem is still with the TransactionController. When requesting it using the url: http://localhost:1607/api/transaction?ID=1. Its not hitting the action.
This the response of the request:
And Its returning back the index view page in the home controller.
Any thoughts why this might happen?