Your Home Network Security app is showing a Guardian app is inactive and cannot be used.
"Unable to use the Guardian app."
This error happens because the device is listed under the Unmanaged Device List.
Remove Inactive Device from the List
- Tap the menu icon.
- Tap Settings.
- Under STATION, tap Unmanaged Devices.
- Tap Manage Devices.
- Tap the - icon next to the device you want to remove.
- Tap the < icon to save the changes.