I have no experience with the Aquara Hub.... but, something I had to do for a Xiaomi Air Filter, was to add a NAT rule so that HomeAssistant (in another VLAN/subnet) appeared to be on the same local network as the Xiaomi (as it will only talk to/respond to devices in its local subnet). Was a bit of a head-scratcher for a while.Basically an egress NAT rule, so that Home Assistant appears to be the IoT firewall IP (on the IoT VLAN), when it tries to reach the Xiaomi (which has its own IP, on the IoT VLAN/subnet). In my case, anyway.It should be possible to work out if it's an mDNS problem, however:- Connect a computer to the same VLAN as the device that needs to 'see' the announcement- Run a mDNS debug tool on that VLAN- See what it sees..mDNS is just the announcement of where to find the announcing device, on what port, sometimes things like supported encryption, etc, however. I'm not clear from your post, if you've allowed the actual communication ports between the device(s)?On macOS, I've used the below (Discovery) a number of times for helping to troubleshoot (or, just to rule out mDNS as being at fault) similar problems:https://apps.apple.com/gb/app/discovery-dns-sd-browser/id1381004916?mt=12