UI Element does not get updated in an async Task from the ViewModel

Hey guys,

I'm trying to add the MVVM to my project but it doesn't work as expected.

In my View I have a label bound to a text in my ViewModel and a Button bound to a Command like this:

<Label Text="{Binding MeinText}"
             FontSize="Medium"
             VerticalOptions="Center"
             HorizontalOptions="Center"/>
      <Entry Placeholder="Username"/>
      <Entry Placeholder="Password"/>
            <Button Text="Command Test"
              Command="{Binding ConnectCommand}"/>

In my ViewModel I connect to a webservice but the label is never updated.
The Text of my Label is always "Test Text". Does anyone know what I should change or where my fault is that MVVM is not working right?

{
    public class HomePageViewModel : ObservableObject
    {
        public Command ConnectCommand { get; private set; }

        string _meinText;
        public string MeinText
        {
            set
            {
                _meinText = value;
                SetProperty(ref _meinText, "MeinText");
            }
            get { return _meinText; }
        }

        public HomePageViewModel()
        {
            _meinText = "Test Text";
            ConnectCommand = new Command(async() =>
            {
                await Connect();
            });
        }

        async Task<bool> Connect()
        {
            ObservableCollection<RootObject> obcl = new ObservableCollection<RootObject>();
            // TODO: dataservice abfrage
            try
            {
                obcl = await Task.Run(() => DataServices.Instance().GetProjects());
                if(obcl.Count == 0)
                {
                    _meinText = "Connected";
                    return true;

                }
                _meinText = "Not Connected";
                return false;
            }
            catch (Exception)
            {
            }
            return false;
        }
    }
}