All matter thread devices won't pair

[EricKit]

iOS device model, version and app version

Model Name: iPhone 16
Software Version: 26.3.1
App version: 2026.1766

Home Assistant Core Version
2026.3.1

Describe the bug

I am receiving this same issue on iOS 26.3.1 on all of my thread devices. I cannot pair them with the Companion App. I have factory reset them and tried multiple times.

To Reproduce
Pair a thread device on iOS 26.3.1.

Expected behavior
Correctly pairs.

Screenshots

Additional context

There is an Apple TV Thread network near by that I don't control and credentials on my phone (debugging->thread) I cannot delete (ha-thread-ccb6), however it is using the correct preferred network (ha-thread-ccb6) as shown in the logs.

matterComissioningHandler(incomingMessage:) > Matter comission received preferredNetWorkMacExtendedAddress from frontend: Optional("0206eedb83212eb5")
2026-03-10 16:07:16.383 [Verbose] [main] [WebViewExternalMessageHandler.swift:360] matterComissioningHandler(incomingMessage:) > Matter comission received preferredNetWorkActiveOperationalDataset from frontend: Optional("0e080000000000010000000300000f4a0300000c35060004001fffe002081278f2de9edb36880708fd26fce3e262ffc50510c1be0d2d9e068f4c7dd5f6ba76559dfa030e68612d7468726561642d36326566010262ef04106370ee5d39bdf87f063e76861dd24d0a0c0402a0f7f8")
2026-03-10 16:07:16.383 [Verbose] [main] [WebViewExternalMessageHandler.swift:364] matterComissioningHandler(incomingMessage:) > Matter comission received preferredNetworkExtendedPANID from frontend: Optional("1278f2de9edb3688")
2026-03-10 16:07:20.450 [Verbose] [com.apple.NSXPCConnection.m-user.com.apple.ThreadNetwork.xpc] [WebViewExternalMessageHandler.swift:401] matterComissioningHandler(incomingMessage:) > Succeeded saving thread credentials in keychain, moving forward to matter comissioning
2026-03-10 16:07:56.682 [Error] [com.apple.root.user-initiated-qos.cooperative] [MatterWrapper.swift:72] commission > Matter pairing failed: Error Domain=com.apple.MatterSupport Code=1 "(null)"
2026-03-10 16:07:56.682 [Error] [main] [WebViewExternalMessageHandler.swift:477] comissionMatterDevice() > Error Domain=com.apple.MatterSupport Code=1 "(null)"

This looks very similar to the closed issue #2574

[bgoncal]

Since according to the logs it was successfully able to save the credentials in keychain, it means the network was found, credentials were matched and network was used for pairing.

All indicates it failed for another reason unrelated to credentials.

[EricKit]

I thought so too. Is there a way to get more log data to figure out where it failed? I've tried to pull logs from the matter server on debug / verbose, thread, and the companion app. I have several devices that won't pair.

I'd like to find more about the "Matter pairing failed: Error Domain=com.apple.MatterSupport Code=1 "(null)" line.

I want to learn more about the commissioning process to understand where it is failing in the process.