I am experimenting building app with buildozer, and yesterday, I built my app to apk, and it installed well.
But today, I built same app except, I deleted Window.size in main.py code. And I installed app but then it says app not installed. Just that. Without any warning or error.
Unless I typed some characters by mistake in buildozer.spec file, my spec file was same, too.
Why this happens? And this is about window size?
The problem occurs because of the previous version of the app conflicts with the current version you are installing.
This may occur if you made some changes in the buildozer.spec which conflicts the previous version
Not because of the play protect
You can just uninstall the previous version to solve the problem :)
Here is a bonus answer
If you want to sign in your app without uploading it to the google playstore so that play protect wont block your app you can refer to this youtube video which i linked below :)
I solved this after some testing.
I disabled Play Protect in Play store, and deleted previous version of app. Then it installed correctly.