I had similar issues a few years ago. I use my SBT to stream from my Vortexbox (Linux-based) server. Try going to the GUI on a networked computer in your home, by entering the IP address for the SBT. Once there, open the Logitec server page and look for a dropdown box labeled "player". You should see your SBT as a choice there. Select it. You may need to reboot your SBT and/or your iMac, too.
Having problem with Logitech Squeezebox Touch switching libraries
I listen to Tidal on library called "mysqueezebox.com". My "stored" music (on my iMac hard drive, downloaded music and ripped CDs) is on a different library. My LST won't switch libraries. When I go to "switch libraries" in the on-screen menu, it just sits and "spins". This happens on both a wired network connection and on wireless connection. Right now I am listening to Tidal. Can not play my stored music thru the LST. Any suggestions would be appreciated. Thanks, Matt