I'm getting this message with I try to add a shape file to a map, "Failed to add data, unsupported data type."

[RonenSaggir]

This problem occurs after working a couple of hours with ArcGIS pro (version 2.4.1) - shapefiles that were loaded correctly before, now throwing exception "unsupported data type " 

CIMStroke polygonOutline = SymbolFactory.Instance.ConstructStroke(ColorFactory.Instance.CreateColor(color),                                              2.0, SimpleLineStyle.Solid);
CIMPolygonSymbol polygonSymbol = SymbolFactory.Instance.ConstructPolygonSymbol(ColorFactory.Instance.RedRGB, SimpleFillStyle.Null, polygonOutline);

await QueuedTask.Run( () => {
                                                   layerToAdd = LayerFactory.Instance.CreateLayer(new Uri(layerPath), viewMap);
});

  the layer path is correct ( i checked).

anyone have ideas on how to solve it?