This happens when devices lose connection to your home hub. First, check if your iPad, Apple TV, or HomePod mini is powered on and connected to the same Wi-Fi network. Restart the hub device by unplugging it for 30 seconds. If specific accessories still appear offline, move them closer to the hub or your router. Some devices drop connection after router firmware updates, so power cycle the accessory itself. For Thread-enabled devices, make sure you have at least one Thread border router active in your home.
Location-based automations fail when Background App Refresh is disabled for the Home app. Go to Settings, find Home app, and enable this option. Time-based automations might skip if your home hub loses internet connection. For sensor-triggered automations, check the battery level of motion or contact sensors. If you have multiple hubs, one might be unstable and causing conflicts. Disable one temporarily to identify the culprit.
The home owner must invite users through the Home app, not through device-specific apps. Each invited person needs their own Apple ID and must accept the invitation on their iPhone or iPad connected to the internet. Shared users won't have access if they're not on the same Wi-Fi network and the home hub isn't properly configured. Check that your hub device shows as 'Connected' in Home Settings. Remove the user and re-invite them if permission issues persist.