Homekit

In the Home app on your iPhone click on the home icon, swipe to the bottom of the displayed list, select Home Settings and select Home Hubs and Bridges. In the resulting list, which hub is connected and which are on standby?

Try turning the "connected" one off (unplug if a Homepod) and see if you still get notifications. If this is the case it might have poor wifi connection (can you move it closer to the router) or be faulty.

Otherwise try restarting your router, as suggested above. Another possibility is wifi interference which is a complex topic - do an online search for advice.

Hi Rich1848,

Thanks for contacting Apple Support Communities!

We understand that your accessories report they're not responding in the Home app occasionally.

If you have all accessories turned on and your iOS device has Bluetooth enabled when this happens, you can power cycle your Wi-Fi router or modem to attempt to reset the alert.

If you still experience the same behavior, you may need to delete the accessories from the Home app then set them up again or restore the accessories to their factory settings.

You can learn more about setting up notifications for your HomeKit accessories here: Get notifications for your HomeKit accessories

Take care!