@theducks:
If your devices are on different wifi bands then it is very possible that zeroconf broadcasts are visible but connections do notwork. A lot of routers require explicit permission for connecting across bands.
If you send me a CC debug log (CC Settings, scroll to the bottom) then I can tell you what CC is seeing. If you send one, please remove the multipie address. No reason for my son to spend time on something I am working on.