I’m having the same problem with the Sonos desktop app since updated my MacOS to Sonoma 15.0.  I’ve allowed Sonos under the firewall, but that didn’t work.  I turned off the firewall completely, but that didn’t work either.  Seems safe to say that this isn’t a firewall issue at all, but just another Sonos incompetence issue.

Any ideas how to work around this latest Sonos blunder?