[bug] Impossible to re-pair new device and bridge to homekit after first pair and delete

[tiziano149]

Hardware

Arduino Nano Matter

Core version

2.1.0

Arduino IDE version

2.3.2

Operating system

macOS 14.5

Radio stack variant

Matter

OpenThread Border Router device (if using Matter)

Apple TV4K and HomePod Mini

Issue description

After initially pairing the Arduino Nano Matter with HomeKit and properly decommissioning the device before deleting the bridge, it becomes impossible to re-pair the bridge to HomeKit. The first re-pairing attempt returns the expected “This accessory is not authorized” message, but subsequent attempts result in a timeout error, preventing the bridge from being added back to the HomeKit setup. This behavior is consistent across both Apple TV 4K and HomePod Mini.

Steps to Reproduce:

1.	Pair the Arduino Nano Matter with HomeKit successfully.
2.	Properly decommission the device from HomeKit.
3.	Delete the bridge from HomeKit.
4.	Attempt to re-pair the same Arduino Nano Matter bridge with HomeKit.
5.	The first attempt results in “This accessory is not authorized” (as expected).
6.	Subsequent attempts result in a timeout and the error “Accessory Cannot Be Added - Failed to establish a link with the accessory.”

Expected Behavior:
The bridge should re-pair with HomeKit without any issues after being decommissioned and deleted, even if the first attempt is unauthorized.

Actual Behavior:
The first re-pairing attempt shows “This accessory is not authorized,” but the subsequent attempts time out and fail with the error message “Accessory Cannot Be Added - Failed to establish a link with the accessory.”

Environment:

•	Arduino Nano Matter
•	HomeKit
•	Apple TV 4K and HomePod Mini
•	iOS version: 17.6.1

Additional Context:
This issue occurs on both Apple TV 4K and HomePod Mini, indicating that the problem is not specific to a particular device. It seems related to how HomeKit handles re-pairing after the initial decommissioning and deletion process.

Serial output

No response

RTT output (if using Matter)

No response

Minimal reproducer code

No response

[Nephylie]

I have the same problem with my home assistant and a GL-S200 Thread border router.

[leonardocavagnis]

Hi,
Did you successfully manage the decommissioning process on the Arduino Nano Matter side?
You can find more details here.

[tiziano149]

Hi,

Did you successfully manage the decommissioning process on the Arduino Nano Matter side?

You can find more details here.

Hi,
Thanks for the reply.
Yes, as stated in the first sentence.

[leonardocavagnis]

Did you try using new provisioning data?
https://github.com/SiliconLabs/arduino/tree/main/extra/arduino_matter_provision

[tiziano149]

Did you try using new provisioning data?

https://github.com/SiliconLabs/arduino/tree/main/extra/arduino_matter_provision

Yup, tried all the different codes.
As it allows to connect to a new border router but then no more than once to the same one, it seems to me more of a caching issue on HomeKits side. Or some credential being stored and then causing the issue. But no idea how to get rid of it...

[Nephylie]

I haven't tried it yet, but I found this :
https://support.apple.com/en-us/102135

[leonardocavagnis]

Hi,
I replicated your setup and everything worked fine. I'm able to commission and decommission the same Nano Matter without any issues.

Arduino Nano Matter
HomePod Mini (A2374)
iPhone 12 (iOS 17.6.1)
HomeKit app

Please, could you clarify the step 2? To decommission it, I only perform step 3 (see attachments).

2.	Properly decommission the device from HomeKit.
3.	Delete the bridge from HomeKit.