Whatsapp: iPhone to Android: 0 messages restored

I backed up my iphone's whatsapp chat history and tried to restore it to my Samsung galaxy s6 when install whatsapp. I've tried this countless times and always got 0 messages restored (also making sure to uninstall the app every time I try again). I even rebooted the phone, but none of it helped. and yes, I redid the icloud backup that time.