The Homekit integration has been working fine for months then yesterday all devices had an unresponsive error message. I power cycled the ATV and HE, left them off for 15 minutes or so, first powered on the ATV then the HE about 5 minutes later. This had no effect. So, I removed the HE from Homekit and now I get an Accessory Not Found error message when trying to add it back.
Long story short, I totally reset my ATV to factory defaults and nuked the Homekit integration, upgraded HE to 2.3.5.152, but still getting the Accessory Not Found error message. I have always had the HE on a separate IoT VLAN and everything had been working fine (all UniFi network). The only change I have made to the network, other than rebooting the router and switches, is enabling mDNS on the IoT VLAN. mDNS was already enabled on the default LAN.
I have not tried moving HE to the default LAN yet and would like to avoid that if possible. Any help or ideas appreciated.