have you tried adjusting firewall settings for the MAC

https://support.sonos.com/s/article/2058?language=en_US

Hi and yes! Firewall settings changed as per sonos but still no luck! I had the library loaded when I first went to Sonos system but lack of use seems to have taken it away!!!

From within the app on the Mac - I think you can still set the library from there.   The iTunes library resides on the mac doesn’it it.

If you haven’t shared the Music folder on your computer yet, follow these steps:

Using the Sonos app for Mac or PC:

1. From the menu bar at the top of your screen click Manage then Music Library Settings.
   • On a Mac, click the + (plus) button
   • On a PC, click the Add button
2. Depending on where your music is stored, select In my Music folder or In another location on my computer, or an external drive connected to my computer.
3. Follow the on-screen instructions to complete adding your music folder.
4. Once the process is complete, click Music Library > Imported Playlists from the Sonos music pane to view and play your playlists.

Thanks. I have seen these instructions on the Sonos web site. My problem is that I cannot connect to my Sonos system via my Mac. I can see the “Manage” tab on the Sonos menu bar but this is greyed out so will not open. The screen is asking me if I want to connect to my existing system or set up a new one.

When I try to connect to my system it cannot be found., It then asks to press the buttons, which I do and they flash on my nearest speaker (Play 1). However, the connection does not get made! 

Setting up a new system is only possible on a mobile device (NOT a Mac). The following appears.

1. Open the Sonos app, select "Set up a new Sonos system," then create or sign in to your Sonos account. This option is not available on the Sonos controller for Mac or PC, only on the mobile controllers.
    
2. When asked "What are you setting up?", choose the relevant option and follow the in-app instructions to complete the setup.

MY PROBLEM is that I cannot see the "Set up a new Sonos system," 

I Can get to “Music Library Set up” and “Add Shared Music Folder” but it asks for Share info which includes Path\\computer\\sharename.

I don't know what to insert here!

I have the same problem as stanners55 -

Sonos has worked on my iMac for a long time but I think the problem has started since upgrading to macOS Catalina 10.15.3 

I have tried all these suggestions. I have also deleted the Sonos app and downloaded version 11.0 again. I also reset my speaker and amp to default and re installed via the iPad app. My Sonos speakers and amp work fine from the app on my iPad but I can't get my music library stored on the iMac.

Amazing - just as I type the above the Sonos app suddenly sprung to life on my iMac - Thanks who ever sorted this out- hope it solved it for stanners55 as well! and that the solutions lasts.

Cheers - John

After my excitement of the app suddenly starting to work on my Mac - This did not last long.

After I exited the app and then opened it again today I was presented with the same ‘Sorry, we can’t connect to Sonos’

SO what is wrong???

It still works on the iPad but the iPad can't find the Music Library on the iMac.

It sure sounds like you have two different sub nets running, and yourMac and iPad are connecting to two different signals. Are you running any access points, Wi-Fi extenders, anything other than a single router?

I would recommend that you submit a system diagnostic from your iPad, and contact Sonos Support to discuss it.

I usually suggest the phone folks, they have more tools available, but are available Monday through Friday during business hours. Twitter support folks are available 24/7.

There may be information included in the diagnostic that will help Sonos pinpoint the issue and help you find a solution.