The peripheral_nfc_pairing sample code pairs and connects, but Android shows a "Couldn't pair" message

[Matin]

I have been trying to use the `nrf\samples\bluetooth\peripheral_nfc_pairing` sample code on the nRF Connect SDK v3.0.2 to connect to a Samsung Galaxy A16 5G phone.

The NFC pairing seems to work, and the connection is working. However, every time the pairing is done, after 20 seconds, I get a message pop-up toast from the Android OS saying "Couldn't pair with Nordic_NFC_pairing". See the screenshot below that shows the pop-up and the bonded connected state of the nRF Connect app. I have also tried clearing the bonded devices on both the nrf5340dk and the phone, but it looks the same.

I have seen people reporting a similar issue before:

•  NFC Android Pairing warning "Could not connect" 
•  NFC pairing failed!!! ble_nfc_pairing_reference test failed!  

Given that the items above are all very old. I was wondering if there are any updates on this.

How do you suggest that I hide the pop-up toast message?

[Hung Bui]

Hi Matin, 

What the pop-up show is that the pairing was not successful. Have you tried to test using another phone ? 

The NFC pairing you did, was it with OOB ? 

Did you try to test pairing the phone with the device without using NFC ? 

I would suggest to capture a sniffer trace to see what exactly goes wrong when pairing. I would suggest to take a look at chapter 5 and 6 in our dev academy here: 
https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/lessons/lesson-5-bluetooth-le-security-fundamentals/

https://academy.nordicsemi.com/courses/bluetooth-low-energy-fundamentals/lessons/lesson-6-bluetooth-le-sniffer/

[Matin]

Hung Bui said:

What the pop-up show is that the pairing was not successful. Have you tried to test using another phone ? 

I know it says it is not successful, but I can see the device in the paired Bluetooth items, and I can interact with characteristics in the nRF Connect app. If the pop-up hadn't shown, I would have never suspected anything. Yes I have tried with other phones and I am seeing the same pop-up.

Hung Bui said:

The NFC pairing you did, was it with OOB ? 

I used the `nrf\samples\bluetooth\peripheral_nfc_pairing` sample code here and I haven't edited any configurations.

Hung Bui said:

Did you try to test pairing the phone with the device without using NFC ? 

On another firmware code, yes. The phone can pair fine without using NFC. But using NFC, it shows a pop-up similar to the sample. The sample doesn't support pairing without NFC. So I thought it would be easier to let everyone try the sample instead of sharing my code.

Hung Bui said:

I would suggest to capture a sniffer trace to see what exactly goes wrong when pairing.

Here is the sniffed capture: sniff.pcapng.gz

[Matin]

We have done testing on more phones, and they all share the same behaviour:

• Samsung A16 5G

• Samsung S10

• Samsung Galaxy A16

• Sony Xperia Z5 (Lineage OS 19)

• Google Pixel 9

• Google Pixel 7

All Samsung phones use the message "Couldn't pair with Nordic_NFC_pairing" and other phones use the message "Could not connect Nordic_NFC_pairing"