Doesn’t work in what way?
Out of sync with the picture or no sound from the HomePod?
- Force close the youtube App & Restart Apple TV - try this first
Are HomePods on the same home wifi Network as The Apple TV and the iOS device used to set up HomePod? You can check the network Homepod is on by going into the Home App on your iOS device and long press on the HomePod icon to bring up settings - tap on the gear icon- lower right - scroll down to WIFI ADDRESS- tap that to display the name of your network
- Make sure that your iPhone, iPad, or iPod touch is updated to the latest version of iOS.* the device used to set up HomePod
- Check that your iOS device has Bluetooth turned on and is connected to your home Wi-Fi network.*
- Update tvOS software
- Reboot your wifi
- unplug the HomePod for 30 seconds, plug back in
- On the Apple TV - Settings- Network- Forget Network & Restart Apple TV then add the wifi back
As a last resort you might need to reset HomePod but usually it’s the wifi not connecting with Homepod or a mismatch of the iCloud account not all being the same one used across devices.