I was trying to replace a boundary for a place with a new kml. I downloaded the boundary as an ESRI shape and used the tool in ArcMap to convert it to a kml. I tested the kml in Google Earth and it looked fine.
When I tried to replace the boundary for an existing place, I got the error that my kml didn’t contain any polygons. I tried exporting from Google Earth in case the ArcMap format was to blame, but that didn’t solve the problem.
I noticed that the file in Google Earth looks like this:
The actual polygons are not at the top level of the file, they’re within a folder in the file. When I right-clicked at the polygon level and exported again, I was able to use the file to replace the place boundary.
So if your polygons are not at the top level of the file, it won’t upload as a place boundary. This might be the reason that some users have had trouble getting their files to upload.