Maybe see if this will help…

https://support.sonos.com/en-us/article/configuring-macos-firewall

Yep, I tried that.   Sonos is already set to accept all incoming connections and I still get the same error.   Any other ideas?

There’s this link too…

https://support.sonos.com/en-us/article/configure-your-firewall-to-work-with-sonos

Although I would perhaps try uninstalling the App and reinstalling it and connecting it to the ‘existing’ Sonos system and let the App configure the firewall for you.

Thanks for your continued help Ken.   Unfortunately those didn’t work either.   I was hopeful the uninstall/reinstall would work, but no such luck.

I’m really not sure then, as I’m not familiar with the firewall, maybe see if anyone in the Apple/MacOS community can perhaps assist you, or perhaps go onto speak with Sonos Support Staff via this link:

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

I’m having the same problem. Sonos suddenly refuses to work and throws up this Firewall issue.  But all the Firewall settings on my Mac are fine.  And Sonos is working on my phone.

This is just one more example of the many little ways Sonos keeps coming up with to make me regret I ever bought the system

Hallelujah!     I got it working (it had nothing to do with the Firewall, despite the stupid Sonos popup box) by following the reply I found on a different thread.  Here it is - it worked for me and for someone else who responded, though it didn’t work for everyone - in case it works for you:

• Surfdog_2003

Got mine working again by going to System Settings > Privacy & Security > Local Network and toggled Sonos off and then back on. Restarted the Sonos desktop app and now it connects. Weird.

Apple caused this chaos, just like they did years ago when they added this permission to iOS.

Sonos need to update the message in the app, their documents, and their notes to their Support folks to cover this new roadblock Apple threw down.

I’ve been an Apple user for years which includes Mac’s. I have to respectfully disagree that Apple has set a road block in Mac security privacy center. All that is required is that the Sonos app be given permission to update and make changes in the background. The Mac OS will prompt the EU to do so if desired. One just has to be familiar with how to navigate within System Settings.

I’ve used Windows in the pass and quite often third party software would jack-up the Windows OS as it made changes that really required a bit more EU interaction to properly integrate it.

However, I do agree that Sonos needs to be more proactive regarding what may be required to use Sonos software on a Mac.

Please don’t be an Apple apologist for this one. The idea of the permission is good, but Apple have done a terrible job with it on iOS and now MacOS. Here’s why:

• Apps cannot tell if the option is on or off, to warn the user and generate decent messages for them
• The automatic prompting when an app first tries to do this is unreliable on both platforms, and if the user accidentally dismisses it the first time they have no idea later how to get it back. (See item #1 above)
• The option has three states: never, on and off. There is literally no way to test ‘never’ more than one time per hardware device (on MacOS).
• Sometimes after app, OS or device updates, the setting is lost, and the user is never prompted.

All of this would be workable if #1 was fixed: when the iOS option appeared, devs begged on the forum for Apple to give a way for apps to tell what the setting state was (like many other permission settings), and years later they still haven’t. This is 98% on Apple (and 2% on Sonos for not updating their docs).

I’m not being an Apple Apologist by any stretch of the imagination.  Not that it matters in the grand scheme of things but I’m a product of the 1950’s. What that means is that I grew up with Microsoft in its infancy with the basic Disc Operating System (DOS) long before PC’s were a thing. I go back as far to using computer mainframes with punch cards; and woe be unto anyone who dropped them and got them out of order. Been there...done that 

My point being is that for every inconsistency/fault you might find with Apple products (in this case MacOS) if I were to expend the energy/time I could counter with a MS inconsistency/fault of equal and/or greater magnitude. I don’t know how old you are but MS had some real doozies with their OS. One that you might remember is Windows ME  the successor to Windows 95 and 98. Below (at the end) are points about ME copied from the web.

I realize this is not about WindowsOS vs MacOS. It’s about EU satisfaction and understanding of the MacOS with Sonos without having to be an expert regarding the “ins and outs” of MacOS. Having been an Apple Advisor (for iOS and MacOS) I’m probably a bit bias when it comes to faulting the way it works with Sonos. My familiarity with the MacOS is probably second nature to me; and therefore not as frustrating as it might be for those that just happen to own a Mac much in the same manner as they could easily own a Windows PC.  

Off-topic...I’ve never understood why Windows based computers have claimed rights to the moniker “PC” which stands for Personal Computer as a MacBook is also a Personal Computer. . However, the world of speech has many “oxymorons” and/or “conundrums” to baffle the senses 

Anyway, I’ve said enough. I enjoy reading others point of view as I always learn something. I wish the Community had more constructive exchange of ideas and opinions (such as yours) without them devolving into chaos forcing the Moderators to remove language and/or close the thread to prevent further unsavory comment. Take care ​@controlav 

Windows Millennium Edition (ME) was an operating system developed by Microsoft and released in 2000: 

• Compatibility

  Windows ME may have challenges using today's technology. It was the last version of Windows that lacked product activation

• Purpose

  Windows ME was designed for home PC users and was intended to improve the user experience with multimedia capabilities and internet integration. 

• Features

  Windows ME introduced features such as System Restore, Movie Maker, and automatic updates. It also included a Home Networking Wizard to help users set up a home network. 

• Reception

  Windows ME received mixed reviews, with some users reporting positive experiences and others criticizing its stability issues. 

• Release date

  Windows ME was released to manufacturing on June 19, 2000, and to retail on September 14, 2000. It was discontinued 11 months later when Windows XP was launched. 

For anyone having this issue, I just got help from Sonos support and it fixed my problem super quick.  In the Sonos Mac app, I went to the help menu and chose “reset my Sonos controller”.  I then just had to choose connect to an existing system and I was back in business in like a minute…  super easy…  

Hope it helps :-)