Short recommendation
Because the official app often fails on Android 4.4, many users switch to third-party clients designed for older hardware: SkyTube Legacy youtube for android tv 4.4 4 latest version download
You have a newer or different YouTube app installed (e.g., the standard phone version of YouTube). Fix: Go to Settings → Apps → Find "YouTube" → Uninstall all updates / Uninstall. Then try installing the Android TV version. Short recommendation Because the official app often fails