Go to Android Settings > Apps > Snaptube > Storage > Clear Cache. Then restart Snaptube. If the problem persists, uninstall both Snaptube and the plugin, then reinstall from scratch.
Because Snaptube isn’t on the Google Play Store, you’ll need to allow your device to install apps from sources other than the official store. Go to and toggle on “Unknown Sources” or “Install from unknown apps” depending on your Android version. Snaptube Codec Plugin Download