Android parse error: the APK may be for a different CPU/Android version. Download a compatible build and avoid repackaged files.
iOS: restart, sign out/in of Apple ID (if appropriate), check payment method prompts, and confirm your region settings.
If you cannot solve the issue, use official support channels on the store listing or the official site for your region.
Install Problems – Quick Fix Checklist
Android: clear your browser cache, re-download the APK, ensure “Install unknown apps” is enabled for the app you used to download, and confirm enough storage.