This could be for a few different reasons –
1. Tablet is too old or missing required features: koala needs at least Android 8.1 as of 15/09/2025. It also needs “low latency audio” capability. Not all devices have this feature but most do. (Google won’t let you buy an app unless your device has the required capabilities, but you could have bought it from a device that does have the capabilities and trying to install it on one that doesn’t, like your old tablet you found under the sofa)
2. You’re logged in with a different account on the tablet or same account but different country.
3. You’re trying to install it from a country that currently has sanctions imposed on it by the US government (not my choice but Google’s, sorry about that)
4. Google sometimes has trouble with its servers (try again later – they may have fixed the problem)
5. The Google play app is buggy as hell (reboot, clear google play store’s cache)
6. Your internet connection could be having problems. Pls try later or on a different connection.
There is nothing I can do to affect the availability of Koala in the Google play store – all those interactions are between the customer and Google directly.