@emil Thank you for the suggestions. However, I have no extra router or firewall in between, and multicast DNS (Bonjour) is not blocked. I can see the "hap" service running on the Flic hub, but the Home app somehow doesn't. When I enable Homekit for a button, there is no notification regarding access to the local network, access to Homekit data, or anything else for that matter. It just switches to the Homekit button interface momentarily (clearly not working as intended, in other words)
Andras