OTBR error - Failed to perform next registration and mDNSPlatformSendUDP got error 99

[WallyR (Wally)]

The two time sync should not be necessary unless it is bugged.
The second sync is just to check if it is bugged or not.

Matter woes

Make sure you have the correct thread credentials on the Android. On the Android Companion App open Settings → Companion App → Troubleshooting (I think that is what it is called in english, but it list logfiles and other tools to diagnostics as description of the item). In this next window click the Sync Thread Login Credentials (Again it might not be named exactly that, but close to and there should not be that many options and it should be in the bottom) It should say either something with …

[Enjoy-Combi]

You saved my day, doing this and Nuki smart lock added (that is the only device I have right now!

[retel (Peter Norlander)]

@retel

NoBufs

Hey, thanks for the input and sorry for the long delay. Life came in between. I just wanted to mention that I did what you suggested and have also updated to HA core 2025.9.1 and HA OS 16.2 but I still have the same messages in the logs. But the devices works without issue, sometimes the become unavailable for a bit (which is annoying) but I’m not sure it is related.

[elgrazo]

You’re a legend, saved my week. I had the same issue and this solved it, thanks!!!

[Piloups]

You’re a legend, that solved my issue, thank you !

[GuntherS (Gunther Schwarz)]

THANK YOU! That did it for me too (2x renewing thread credentials in Android app). Didn’t even look in this corner of the config. Using an old Sonoff E stick to play with Matter/Thread and the new Ikea Matter devices I thought everything is looking good, but could not add anything. And all of this after spending hours on using a Echo4 as the thread router, which failed misserably. Completely abandonded Echo as thread router and tried the Sonoff. Sonoff is working now just fine.

[benschumacher]

@WallyR

You need to have IPv6 enabled and not run HA multihomed.
You can run Matter with VLANs, but HA, the Matter server, OTBR, phone for commision and devices needs to be in the same network, unless you really learn IPv6.
Your IPv4 knowledge is pretty useless when it come to IPv6.

Hey @WallyR,

Jumping into an older thread here, but you mentioned something here that caught my attention. I appear to have a working Thread installation, though I do see similar errors re: mDNSPlatformSendUDP got error 99 (Cannot assign requested address) sending packet to ....

I do have HA multihomed, which is easy enough to disable, but I’d like to understand what the reason for this is and the impact. I have my network segmented to IoT devices with a different network policy, but it isn’t clear to me why that would impact my Matter-over-Thread devices.

Appreciate the insight here.

Just thinking it through, I could disable IPv6 on one of the interfaces on my HAOS host, but is this something that could be addressed in the software re: ensuring that the mDNS broadcasts are only sent on the appropriate interface? My read of this error message is that we’re trying to bind to a local address to send mDNS packets (I imagine on UDP:5353), but we’re conflicting with another service that’s also bound to this port? (Maybe I need to take this question upstream to the OTBR project.)

Thanks,
Ben

[WallyR (Wally)]

I am not sure why it can not assume gn an address, unless the network is not actually set up at the time it tries to do it.