Homekit Just added new device but an hour later shows no response

without a hub it will only work when whatever that device you are using to control it in present on the same lan network as the device, and vpns can cause issues

also some homekit devices uses bluetooth and that can mean a much shorter range than wifi devices I have a leak detector that does that and it's hit or miss if it repsonds

Since upgrading my HomePods, my smart devices in Home are showing ‘No Response’ or ‘Updating’. I have to unplug my HomePods and let the AppleTV become the default Home hub so I can control the devices.