The "NOT_APK" part of your error means you're trying to install something that isn't an APK. If the file extension is an APK then it's corrupted and you'll need to re-download it.
Yeah, it was some weird bug... The downloaded file had the ".apk" format but was giving the error, but then I had to uninstall and reinstall a few times until it decided to work! Thanks for your attention tho! :)
