Error when importing CityGML file

I’m trying to import a citygml file on cesium ion using FME workbench and i’m facing some issues.

First i had a problem with geometry. Apparently cesium only support closed geometries (screen below).
When i tun a geometry validator on FME and kept only valid geometry i got a new error : Unsupported citygml node (screen below).

Could you please help figure out what the error is about.