The app on my Mac work great.

What speakers do you own? Are they S1 or S2 compatible?

If they are S2, select “check for updates” to see if there are any updates needed?

If they are S1, you may have downloaded the wrong app.

S2 - I’ll record a video. once sec

Here’s a link - should be up in a few more mins:
 

Perhaps try uninstalling the App completely and then try a fresh install of the Mac App from here…

https://support.sonos.com/en-us/downloads?language=en_US

After accepting T&C’s and firewall settings etc. then simply connect the fresh install to the existing Sonos system on the local network.

Hope that works for you.

Nah, re-installed, still doesn’t work.

I would perhaps speak to Sonos support. Here’s the link to contact ‘em..

https://support.sonos.com/s/contact

Hope you manage to get it sorted.

Yes I had a similar problem immediately upon installing macOS 15.0 Sequoia. App was not able to locate my Sonos system  Two long conversations with Sonos support not helpful. I finally found the problem.  

System Settings → Privacy & Security → Local Network

Switch Sonos to “on” position

It worked for me. Did it solve problems for others? 

I hope Sonos support persons will make not of this to help others stranded by Sequoia

Five months now since Sonos intentionally broke our systems.

I still do not have a fix for playing my local library from my Mac. Am told they are working on a solution compatible with the latest Mac OS and the Sonos controller which they forced onto my computer.

How many more months, Sonos????

At this point just hoping to have something cobbled together enough o be a stopgap until I have the funds to fully replace this system. No matter how or when (or if) this is resolved, I will never spend another penny on Sonos gear.

Your customers hate you. Well done.

Thanks for this tip. Sonos was already “on” for me, but I toggled it off and then back on and then the Mac Sonos App was able to connect for me.