java - Android で SendBird ChannelHandler onMessageReceived が呼び出されない

Question

AndroidでSendBirdを使い始めました。1in1チャットをしたいのでSendBirdに接続し、ハンドラを設定し、チャンネルを作成してメッセージを送信しましたが、onMessageReceivedが機能しません。以下のコードを参照してください。

var handler = object : SendBird.ConnectHandler{
        override fun onConnected(p0: User?, p1: SendBirdException?) {
            SendBird.addChannelHandler(UNIQUE_HANDLER_ID, object : SendBird.ChannelHandler() {
                override fun onMessageReceived(p0: BaseChannel?, p1: BaseMessage?) {
                    Log.d(TAG, "addChannelHandler  - onMessageReceived - messageId ${p1?.messageId}")
                    Log.d(TAG, "addChannelHandler  - onMessageReceived - channelUrl ${p1?.channelUrl}")

                    if (p1 is UserMessage) {
                        Log.d(TAG, "addChannelHandler  - onMessageReceived - messageId ${p1?.message}")
                    }
                }
            })
        }
    }


    override fun onCreate(savedInstanceState: Bundle?) {
        super.onCreate(savedInstanceState)
        setContentView(R.layout.activity_main)

        SendBird.connect("222222", handler)
        SendBird.connect("111111", object : SendBird.ConnectHandler {
            override fun onConnected(p0: User?, p1: SendBirdException?) {
                Log.d(TAG, " SendBird.connect - userID -  " + p0?.userId)

                var list = mutableListOf("111111", "222222")

                var   params = GroupChannelParams()
                params.setDistinct(true)
                        .addUserIds(list)

                GroupChannel.createChannel(params, object : GroupChannel.GroupChannelCreateHandler {
                    override fun onResult(p0: GroupChannel?, p1: SendBirdException?) {

                          groupChannel?.sendUserMessage("Hello", object : BaseChannel.SendUserMessageHandler {
                        override fun onSent(p0: UserMessage?, p1: SendBirdException?) {
                            Log.d(TAG, "sendUserMessage - onSent - ${p0?.message}")
                        }
                    })



                }
            })