If one of your accessory is not connected to your system anymore, a notification message will be displayed. 

As a first step, make sure via the All accessories menu in the ARCHOS Smart Home application that there is enough battery and that Bluetooth® is switched on.

If Bluetooth® on your Smart Home Tablet is off, your accessories will try to reconnect on a regular basis. If the connection is not back within 12 hours, your accessories will enter deep sleep mode andyou will need to manually wake them up.  

Make sure that your Smart Home Tablet is on and that Bluetooth® is on and then press once the pairing button of each accessory to wake them up so they reconnect your tablet. The reconnection can take few minutes.