Microsoft.Practices.ServiceLocation.ActivationException using Xamarin Autofac - xamarin

Question

I am building an aaplication in Xamarin for IOs and sometimes I get these errors.
Microsoft.Practices.ServiceLocation.ActivationException: Activation
error occurred while trying to get instance of type
SurveyNavigationPage, key ""
I can't figure out why am I getting them and can't even trace them to where they are coming from...
I guess I have done something wrong in the Dependancy Injection. I am using Autofac and Service Locator. Below I will demonstrate how I implement the dependancy injection in my project and possibly someone can spot my error.
My code is in the PCL part of the Xamarin project but the error happens iOS Application class for some reason in the UIApplication.Main(args, null, "AppDelegate"); Well at least that is where it crashes if I debug..
My PCL App class instatiates the dependancy injection class like this:
public App()
{
SetUpDIContainer();
InitializeComponent();
MainPage = new NavigationPage(ServiceLocator.Current.GetInstance<MainPage>());
}
private void SetUpDIContainer()
{
var container = new DependencyInjection();
container.Initialize();
}
The Dependancy Injection class looks like this:
public class DependencyInjection
{
private IContainer _container;
public void Initialize()
{
BuildContainer();
SetServiceLocator();
}
private void BuildContainer()
{
var builder = new ContainerBuilder();
builder.RegisterGeneric(typeof(RestRepository<>)).As(typeof(IRest<>));
builder.RegisterType(typeof(PageService)).As(typeof(IPageService));
builder.RegisterType<SurveyController>();
builder.RegisterType<LocationController>();
builder.RegisterType<ClientController>();
builder.RegisterType<RepositoryService>();
builder.RegisterType<MainViewModel>();
builder.RegisterType<SurveyNavigationViewModel>();
builder.RegisterType<EditSurveyViewModel>();
builder.RegisterType<ClientPageViewModel>();
builder.RegisterType<BaseViewModel>();
builder.RegisterType<MainPage>();
builder.RegisterType<SurveyNavigationPage>();
builder.RegisterType<SurveyPage>();
builder.RegisterType<EditSurvey>();
builder.RegisterType<ClientPageView>();
builder.RegisterType<App>();
var http = new HttpClient();
builder.RegisterInstance(http).As<HttpClient>();
_container = builder.Build();
}
private void SetServiceLocator()
{
var csl = new AutofacServiceLocator(_container);
ServiceLocator.SetLocatorProvider(() => csl);
}
}
It is a very strange error as it comes up sometimes and sometimes it doesn't and I can't spot what exactly has to happen in order for it to happen.