Child themes are picky about the names, if you download the zip file two times it will be named zip(1) then it could fail.
Make sure you do not activate the parent theme, only install. If you activate the parent theme it will show child theme as broken. To update a parent theme you must deactivate child theme first.
So, Disable child theme, make sure you only upload iconic-one-pro.zip and and after installation do not click activate, go back to themes dashboard and only activate the child theme.