The device name has disappeared from the Android Bluetooth list.

[moon.kim]

Hi.

I had to unpair from the Android Bluetooth list by doing pm_peers_delete () when bonding.
It's ok. I know why it should.
But sometimes I can't find my paired device in the Android Bluetooth list.
I must unpair before I can pair again. But I can't unpair because I don't see the device in the list.

Eventually I have to reset the network settings.

After that I can pair again.
Why do these symptoms occur?

[moon.kim]

sorry.
I was a bit clumsy to explain.
I'm developing with a custom board and programmed using nordic's Glucose example.
I used BGM in the Nordic ToolBox App.

However, this symptom occurs even with the Glucose  example source and nRF52 DK board.

This order : 

1. Pair the DK board with the BGM app.

2. Disconnect and unpair 'Nordic_Glucose' from the Bluetooth list in Android settings.

3. press 'connect' again in APP, the message 'Error on connection priority request(19)' is displayed.

4. press 'connect' again in APP, and Pair with app.

5. The connected device name is not displayed in the Bluetooth list of Android settings. But now Bluetooth is connected. Thereafter, this device name will not appear in this list.

thank you

[Simonr]

Hi

Thank you for the thorough explanation. I am not able to recreate this issue on my side though, can you give me a list of some phones you've been able to recreate the issue on and I'll try to find someone here who has one of them.

Also, just to make sure. You aren't deleting the bonding information from the phone side when disconnecting, correct? Because if you delete the bonding information on one side, you won't be able to bond with the device again before bonding information is deleted on both sides.

Best regards,

Simon

[moon.kim]

Hi. Simon

I test with Xiaomi Mipad 4 (Android version 8.1) & LG X400(Android version 8.1).

Simonr said:

Because if you delete the bonding information on one side, you won't be able to bond with the device again before bonding information is deleted on both sides.

And I know I have to delete both side pairing information.

But the Bluetooth list doesn't show the paired device. So I can't delete it.

Change the test method a little.

moon.kim said:

2. Disconnect and unpair 'Nordic_Glucose' from the Bluetooth list in Android settings.

Do not delete the pairing information from the Bluetooth list in this order, but delete the pairing information from the DK board.

[Simonr]

Hi

We did not have these particular phones in the office, but I've done some testing myself on a Google Pixel (Android 9) and a Nokia 8.1 (Android 10) and have not been able to reproduce this error. I've followed your steps both ways and tried to unpair first from both sides, but I can't seem to get the error message you're seeing.

I'll try downgrading the Pixel to Android 8.1 next to see if the issue is with the Android version. Are you able to update one of the phones on your side, or try with a newer Android version to see if that gets rid of the error as well?

Best regards,

Simon

[Simonr]

I just downgraded the phone to Android 8.1 as well, and I'm still not seeing this error. I am unable to connect to the device if I delete the bonding information on one side and not the other, as expected, but I'm not able to get the error message you mentioned. Can you try to specify how exactly you unpair the devices? Do you use the nRFConnect app at all?

Best regards,

Simon