An inaccessible device indicates that it is unable to communicate with the GT125. This miscommunication can happen if the strength of the communication signal is too weak. A weak signal is due to a significant distance between the devices or if one of the devices repeating the signal is not working properly.
First, try to reset the connection of inaccessible devices, then reconnect your devices from the closest to the furthest from the GT125. This procedure will allow your devices to find the best communication path to the GT125.
If this doesn’t work or the issue happens regularly, consider reducing the distance between devices by adding a compatible product that can repeat the communication signal.