Install not compatible with 5.1. Help!

Unable to update QBOX 5.1.1 to KODI 17 from 16.1. Or install 17
Looking for help. I have a Q box which runs android 5.1.1 which should be enough to upgrade to KODI 17. But when I go to google play store, when searched, it won’t even show up. Tried from kodi.tv. Also no go. It will download the apk, it just begins to install. Then I get a white screen saying “app not installed”. If I follow the play store link from kodi.tv. It will bring me to the kodi install but I get a message
saying that my device is not compatible. Any help Please? I thought you only needed android 5.0. Why would 5.1 not be compatible? I was able to use update an MXQ PRO 5.1 with no problem.