HI,
I have a raster KMZ's
https://topex.ucsd.edu/grav_outreach/files/global_grav.kmz
If I drag the downloaded kmz file in arcgis Pro it renders fine.
When I publish to ArcGis Online as a web map it works but opening the map it gives a warning and doesn't load it.
The KML is not avialable or cannot be added to the map.
Another one loads but then displays a grey raster with a big red cross.
https://topex.ucsd.edu/grav_outreach/files/global_grav_gradient.kmz
R,
Lennert