Custom shape Map displaying only polygons but no maps

Hello PBI Community

I am trying to build a custom map of Portugal, which means ( Portugal, the Madeira Islands and the Azores Islands). To do that I followed the following link : Create custom map in Power BI. I went to google maps, created a map with 3 polygons (Portugal and the two Islands) exported the map to a kml file, then converted it to a geojson file, then from a geojson file to a topogeojson file. When I imported the topojson to power BI desktop, Only the polygons appear, but not any single land or ocean :( 

Is there a problem on the formats or the tools to do the conversions ?

Thanks in advance

Ziad