Flutter Socket IO not listening to event

I am using socket_io_client package in a flutter app for chatting, when I emit an event from my side to the server side it works well, however I don't receive an event from the server side

Here is the server side code using Node JS and it uses Socket package ^4.4.0

const io = require('socket.io')(6600, {cors: {original: '+'}});

io.on('connection', (socket) => {
    console.log('user connected');
    socket.on('userid', (userId) => {
        console.log(userId);
        socket.userID = userId;
        console.log(socket.userID);
        socket.join(socket.userID);
        // console.log(io.sockets.adapter.rooms[socket.userID].length);
    });
    // send all sockets of the same user to the same room
    socket.on('sendmessage', ({content, senderId, receiverId}) => {
        console.log(content);
        console.log(senderId);
        console.log(senderId === socket.userID);
        console.log(receiverId);
        socket.to(receiverId).to(senderId).emit('receivemessage', {
            content,
            senderId,
            receiverId,
        });
    });
    socket.on('disconnect', async () => {
        const matchingSockets = await io.in(socket.userID).allSockets();
        const isDisconnected = matchingSockets.size === 0;
        if (isDisconnected) {
            console.log('user disconnected');
        }
    });

and here is my flutter code I use socket_io_client of version ^2.0.0-beta.4-nullsafety.0 , I can send the 'sendmesssage' event to the server, but I don't receive 'receivemessage' event

class SocketIO extends ChangeNotifier {
  ///Socket object
  IO.Socket socket;

  ///Connects to socket server using [userId]
  void connectToServer(BuildContext context, String userId) {
    socket = IO.io(
        'http://10.0.2.2:6600',
        IO.OptionBuilder()
            .setTransports(['websocket']) // for Flutter or Dart VM
            .disableAutoConnect() // disable auto-connection
            .build());
    socket = socket.connect();
    print('connection id: ' + userId);
    socket.onConnect((_) {
      print('connect');
      socket.emit('userid', userId);
      socket.on( // not working
          'receivemessage',
          (data) => () {
                print('message recieved');
                Provider.of<Messaging>(context, listen: false).receiveMessage(
                    context,
                    data['content'],
                    data['senderId'],
                    data['receiverId']);
              });
    });

    socket.onDisconnect((_) => {print('disconnect')});
  }

  void sendMessage(String senderId, String receiverId, String text) {
    print(socket.connected);
    socket.emit('sendmessage',
        {'content': text, 'senderId': senderId, 'receiverId': receiverId});
    print('sender id: $senderId');
  }

  void disconnect() {
    socket.off('privateMessage');
    socket.disconnect();
  }
}

I can't find the problem at all