If I upload my KML file, which contains polygons and pins, to Google Maps, then most of the polygons are missing (see below).
To try and address this, I pasted the kml url to the Google Maps search bar and all of the polygons are now shown on the map but all the pins are missing (see below).
The KML file can be downloaded from here.
What should I modify in the KML source to have all polygons and pins in the same map?