If you have a UniFi setup with a Chamberlain MyQ Home Bridge, sometimes it can be flaky under HomeKit. Specifically, the issue that I was seeing was that the garage door opener could be seen and controlled by the MyQ app, but in the iOS home app, both the MyQ Home Bridge and the garage door opener showed the dreaded "No Response" message. It turns out that the issue is that HomeKit WiFi devices tend to use the 2.4GHz band, but your computers and other devices are probably on the 5GHz band. The UniFi router/WiFi access points will silently create 2 networks with the same SSID... one that's 2.4GHz and one that's 5GHz.

Normally that's not a problem, but due to the way that HomeKit discovers devices, it becomes a quite annoying issue. Basically, HomeKit/Bonjour devices advertise themselves using something called Multicast DNS. In some cases, the UniFi software won't send the Multicast traffic between the 2 networks, so your HomeKit bridge can't find the MyQ Home Bridge.

The way that I fixed it was to open the UniFi Controller interface and turn on the setting named "Enable multicast enhancement (IGMPv3)". I found it under Settings > Wireless Networks. I clicked Edit on my wireless network, and then I clicked Advanced Options to reveal the setting. Once I applied that setting, my Home Bridge showed up immediately.