FormsAuthentication.Authenticate always returns false with in asp mvc 4 project

For some reason this FormsAuthentication.Authenticate always returns false when I put in the correct details. However the
 Membership.CreateUser(model.UserName, model.Password, model.Email, null, null, true, null,                                       out status);
works and saves stuff in the db
public bool Authenticate(string username, string password, bool rememberMe) { bool result = FormsAuthentication.Authenticate(username, password); if (result) { FormsAuthentication.SetAuthCookie(username, rememberMe); } return result; }


I've set up the web con ...