no messages received from client MIDIService

[jardous]

I have two Seeed XIAO nRF52840 Sense devices. One is running ble_midi_simplein.py from examples and second one (client) runs following code that is sending messages:

import sys
import os
import time
import adafruit_ble
import adafruit_midi

from adafruit_midi.note_off import NoteOff
from adafruit_midi.note_on import NoteOn

from adafruit_ble import BLERadio
from adafruit_ble.advertising.standard import ProvideServicesAdvertisement

from adafruit_ble_midi import MIDIService 

ble = BLERadio()

while True:
    while ble.connected and any(
        MIDIService in connection for connection in ble.connections
    ):
        for connection in ble.connections:
            if MIDIService not in connection:
                continue

            midi_service = connection[MIDIService]
            midi = adafruit_midi.MIDI(midi_out=midi_service, out_channel=0, debug=True)

            midi.send(NoteOn(20, 99))
            time.sleep(0.5)
            midi.send(NoteOff(20, 99))
            time.sleep(0.5)

        time.sleep(1)

    print("disconnected, scanning")
    for advertisement in ble.start_scan(ProvideServicesAdvertisement, timeout=1):
        if MIDIService not in advertisement.services:
            continue
        ble.connect(advertisement)
        print("connected")
        break
    ble.stop_scan()

However the server (ble_midi_simplein.py) does not show any received messages.

Connection is established and MIDI messages seem to be sent, but never received.

If I send MIDI messages from my phone, the server receives it.

CircuitPython version 8.0.4

[jardous]

Found the issue - pairing is needed here

        for connection in ble.connections:
            if not connection.paired:
                connection.pair()
                print("paired")