The update process usually involves an update to the app then an update to the system.  So I would suggest you go onto a mobile app and ‘check for updates and make sure the app and the system are on latest v14.

If they are then try to update the PC app.  If you still have problems, uninstall the PC app and then reinstall from the Sonos Support site.  Make sure you choose to connect to existing system.

If you've changed router recently, your pc might be seeing it as a public network which can cause issues. If you do a Google search for "change public private network windows" it should be the first result :)

If you change it to a private network, can you connect?

Thanks.  De-install and re-install worked :-)