After many many hours with customer care , I got it working
here is a synopsis of what took place :
6 devices on my system got upgraded to the S2 Sonos os which made them incompatible to the S1 system while two products were S1 and worked .
This is what we did : Disconnect(unplug from
power) all products that were SonosOs S2
then Factory Reset those products via the S2 App => Goto HelpCenter => Sonos S1 Legacy => Downgrade product ….
then in the Sonos S1 app => Add Product to system !
did this six times !!!! But it worked
the explanation of WHY these products upgraded to S2 , is a mystery. The explanation was that some products are Compatible to run on the S2 app while some are not … don’t know
Will leave for another day !