They should, but need node.js running on another device on your network. This of course, is a rather silly situation.
Maybe there is some sort of permissions issue with the Mac? Is node.js accessible from the network? Not an expert on mac permissions and node.js but someone will know if any settings on the mac need changing.
I am going to try installing it in a vm on my NAS but there shud be an easier elegant way of doing this. My wish is that they make it easy to use Roon extensions via app.