I have just purchased a sub gen 1 off ebay for my S1 system. All looks good.
I have another Sub already connected to my lounge, this new one is for the kitchen/beam.
The S1 app could not see the sub. I had this problem with the beam. So ran S2, factory reset, connected, downgraded to S1. All looking good. I run S1 app on same wifi network as Sonos system. Follow instructions. The S1 app finds Sub. Asks me to press the Sub button, I do this, and S1 thinks while trying to connect. But does not and concludes it cannot find the unit (even though it had it in its sights just moments ago). I’ve been round this loop several times, factory re-setting etc. Always, the S1 can see it and begin the connect sequence, but then loses it. What is the workaround?