I have had my system for a number of years and last changed by router (BT Smarthub 2) a year ago and have no problems whatsoever until recently.  My whole system no keeps disappearing so you cannot see it from the controller device.  It isn’t the controller as we use multiple devices ( all Apple) and on each device it will say that it can’t find the system.  My system is a play bar + sub and 2 play 1’s in the living room and 2 more play 1 s in other rooms.   Once the system disappears, if you reset the router it will return but often only for a short while and then connection will be lost again.

If you log into the router it says all the devices are still connected.  (As are the devices) used as controllers

If you connect the play bar by Ethernet the whole system is rediscovered.  Doing the same for other devices is less successful.  The individual device may return but play is interrupted.  If the keeping the play bar connected to Ethernet is a long term solution then I can look at this but at present I would prefer to revert to a wireless solution as I haven’t had any problems until now

Thanks in advance for any help