The S1 controller will continue to work with S1 speakers. If you’ve updated those speakers to S2, you’ll need to go to the Sonos website and download the S2 controller for Mac.
when I tried to connect, the S1 controller said it could not find the speakers. I tried to connect, and it still did not find the one sitting next to it.
Try, at least temporarily, wiring a single Sonos speaker (not a surround or Sub) to your router with an Ethernet cable.
The Mac needs to be on the same subnet as the Sonos speakers. Some mesh systems break up subnets when not configured properly.
If you’re still having issues, call Sonos Support directly to discuss it.
When you speak directly to the phone folks, they have tools at their disposal that will allow them to give you advice specific to your network and Sonos system.