Why status code BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED ?

[MichaelNordicUser]

I'm tring to connect my phone to the multi-connect example client app

I'm tracing the ble events in the ble_evt_handler.

When I open the server app on my phone, I see this in my RTT

BLE_GAP_EVT_CONNECTED
BLE_GAP_EVT_DISCONNECTED
BLE_GAP_EVT_CONNECTED
BLE_GAP_EVT_DISCONNECTED
BLE_GAP_EVT_CONNECTED
BLE_GAP_EVT_DISCONNECTED
...

like the phone is connecting, advertising, and reconnecting over and over...

The when I go BLE_GAP_EVT_DISCONNECTED case statement and print reason for discconnect I get

BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED   0x3E

So I think well why is BLE_GAP_EVT_CONNECTED true if device never connected in the first place according to BLE_HCI_CONN_FAILED_TO_BE_ESTABLISHED?

So then I think maybe there is difference between being connected and establishing a connection?

In the Android code, I've chaned the device name to Nordic_Blinky; therefore the multi-connect client should connect to the Android server right? The Android phone is advertising a Time service, but I don't think that matters here right?

I just can't think of a reason why the phone connects, but the connection fails to be established or what that even means.

Here is my Android startServer method

/**
 * Initialize the GATT server instance with the services/characteristics
 * from the Time Profile.
 */
private void startServer() {
    mBluetoothGattServer = mBluetoothManager.openGattServer(this, mGattServerCallback);
    if (mBluetoothGattServer == null) {
        Log.w(TAG, "Unable to create GATT server");
        return;
    }

    mBluetoothGattServer.addService(TimeProfile.createTimeService());
    
    // Initialize the local UI
    updateLocalUi(System.currentTimeMillis());
}

And here is startAdvertising method

/**
 * Begin advertising over Bluetooth that this device is connectable
 * and supports the Current Time Service.
 */
private void startAdvertising() {
    BluetoothAdapter bluetoothAdapter = mBluetoothManager.getAdapter();
    mBluetoothLeAdvertiser = bluetoothAdapter.getBluetoothLeAdvertiser();
    if (mBluetoothLeAdvertiser == null) {
        Log.w(TAG, "Failed to create advertiser");
        return;
    }

    AdvertiseSettings settings = new AdvertiseSettings.Builder()
            .setAdvertiseMode(AdvertiseSettings.ADVERTISE_MODE_BALANCED)
            .setConnectable(true)
            .setTimeout(0)
            .setTxPowerLevel(AdvertiseSettings.ADVERTISE_TX_POWER_MEDIUM)
            .build();

    boolean isNameChanged = BluetoothAdapter.getDefaultAdapter().setName("Nordic_Blinky");
    if(isNameChanged) Log.d(TAG,"Device name changed successfully.");

    AdvertiseData data = new AdvertiseData.Builder()
            .setIncludeDeviceName(true)
            .setIncludeTxPowerLevel(false)
            .addServiceUuid(new ParcelUuid(TimeProfile.TIME_SERVICE))
            .build();

    mBluetoothLeAdvertiser
            .startAdvertising(settings, data, mAdvertiseCallback);
}

[Aleksander Nowakowski]

Are you sure the your DK isn't bonded to the Android phone? For example you could have had another app flashed with bonding, bonded it to the phone and then flashed the multiconnect sample, but the bond info is still present on the phone. Check in Android Bluetooth settings.

Also, did you try setting the GATT server and advertisement in nRF Connect on Android? Does it work for you or behaves the same way?