I have a Mac run-on El Capitan and I have what I think is a firewall problem using Sonos. When I load the Mac Sonos Contoller I get a box that says 'Do you want the application “Sonos.app” to accept incoming network connections?' with Deny or Allow options. Clicking on Allow attaches to my music OK. If I turn the Firewall off then this box does not appear.

I have my Firewall set up correctly as per Sonos guidelines with Block all incoming connections not checked and Sonos App included to accept incoming connections.

I've tried reinstalling the Sonos Controller software and deleting/readiing my Music share which is on a NAS. As far as I know I have changed nothing to cause this and it just started happening yesterday.