I have a full Arc SL home theater up and working just fine (except for that little part about Atmos...), and the S2 app is running on my iOS devices just as fine. I installed the MacOS version of S2, and it doesn’t see the Arc. I get the following message:
Your Sonos product was not found. If your product is a long way from your router, you may need to try moving it closer.
Please select “Try again.”
For information about firewall configuration and other potential network problems, go to…” etc.
None of that applies to this install. The Arc is working well, and its farther away from the router than my desktop iMac, which is about 20 feet away from the Arc. This same desktop had no trouble working with a prior Playbar, using the classic (pre “S1”) Sonos controller app.
I’ve searched and read all the articles that might apply to this situation, and there’s no advice for this specific dialog box.