Been using the beta HomeKit app for a few weeks now. Until yesterday it's been really stable for the subset of devices that it supports. Since Sunday my internet provider and my power company have been having difficulties and my internet has been up and down several times a day, with power glitches once or twice over the same period. I live out in the country, so this is normal for me, and one of the major reasons I switched to Hubitat and its model of running the code on the hub locally.
In the extra flakey environment the last few days the HomeKit app has been very inconsistent and usually shows "No Response" or "This accessory is not responding". When I open up the Hubitat web interface directly, everything is running fine. Usually rebooting my Hubitat hubs corrects the problem, but not always.
Do you have a device acting as a Home Hub, i.e. HomePod, HomePod Mini, AppleTV, etc.? If not, then the only integration point would be the Apple Cloud, and if your internet has been an issue.... (might also be an issue if you have one of these, but certainly without one.)
Yes I have multiple Apple TVs and multiple Hubitat Hubs on the same network. Unfortunately there's no easy reset/refresh button on the Apple TVs or the Home App (typical "Apple Magic" - it just works... until it doesn't and then there's nothing you can do about it because you don't get any troubleshooting tools). Mostly posted this as a bugrep for the hubitat team. Aside from rebooting there isn't much troubleshooting I can do. Out in the country power and internet will keep going down, and all I can do is buy into tech solutions that are designed to be resilient.
I have a HP mini on a backup power supply with my Homebridge server. I haven’t tried it yet with the Hubitat integration, but when everything was on Homebridge it kept working with brief power outages (generally caused by me while remodeling).
P.s. I also have my hubs on a backup.
I tried homebridge years ago before it was stable and gave up on it... because it wasn't stable lol. Maybe time to try it again. I was hoping the official integration would be good. I could live with the limited devices, but if it's going to keep needed a kick every time the environment gets flakey then I'm out. I've been enjoying finally having Siri control after years of using spit and glue to make things work though, so probably need to figure something out.