Homekit hub (ATV 4K) cannot pair with HE

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.

Given all the reseting you've tried, I'd suggest:

Screenshot 2023-09-02 at 1.21.21 PM

...down at the bottom of the Integration.

Don't know if it's related or not, but I have never been able to add my C8 to either of my ATV 4k’s. C7 works ok, not the C8. I've been going back and forth with @gopher.ny , but so far no resolution.

I left everything alone for 4 hours or so and then reset the QR and pairing code again, and now it works! Hopefully this will continue as everything has been working well for me since the Homekit integration was released. Thanks for the tip.

This one is a C-7.