Some day ago I've updated Umbraco to 7.4.1 from 7.3.x, both in my local installation and the online (production) one. Today I've found this error online only:

Could not find the surface controller of type LoginController

I have a View Login.cshtml that render a Partial View Login.cshtml:

@{ Html.RenderPartial("login"); }

and inside the Partial View I have this code:

@using (Html.BeginUmbracoForm<LoginController>("HandleLogin"))
{ ... code ...}

I have a controller in the App_Code directory that inherits from SurfaceController:

public class LoginController : SurfaceController

It works for months, but now it gives me the error. In the local copy of the Umbraco installation it works as before so I don't understand what's wrong with the production version.

I've read some old post about this topic here in the forum, but I can't understand where the error is. What's wrong? Thanks in advance, Joe