Home Hub shows "Standby" on iPhone

I have one HomeKit Hub on my Apple TV. It has had an automation that has been set up since I got the Apple TV years ago. The location automation is working to turn outside lights on when I arrive home. I want to change this automation to add another light. I have tried to do this using the Home app on my iPhone. I can enter the change, but upon clicking "Done" to save the change I get the message "Could not edit "Location Automation". At the top of the Location Automation pane it says "Home hub not connected. To ensure your automations run as expected, connect a home hub." Yet on the Homes & Bridges pane under Home Hubs is listed "Family Room Apple TV - Standby." Two bridges are also shown for my garage doors and Lutron controls. Has anyone solved this problem?