I have had a matter network setup with HA for about a year now, and have around 30 devices on it. The last time I added devices was around 5 months ago, and they process worked well.
I just got some new devices, and I went to add them through the iOS companion app. Almost no matter what I do I cannot get them added. The app always says "Unable to Add Accessory, home couldn't connect to this accessory." I have tried over 400 times at this point, and just once did one device pair, and it works fine.
I have tried verifying my thread credentials, removing old ones, syncing them again. I have simplified my thread network by taking of all of the apple BR but 1. I have tried using the open border router.
I have a unifi network, but all the standard settings are set, and I have not changed anything from when I could add devices. HA can see the existing devices mDNS and multicast traffic fine.
When I try to pair a device, I can see the status indicator light saying to was correctly added to the network, but it is like it just fails at this point. I have factory reset and tried again many many times. I have tried with more than one device type, same result.
I am at a bit of a loss here, because I don't see any indication of anything happening in the logs on HA server side, so I don't really know where to dig in from here and am hoping someone here has some ideas where to point me. I really don't know if this is a server issue, an app issue, or an iOS issue, or some combination of these. The fact that I was able to get one device to pair once is what is confusing me even more.