Socket.io won't send/receive messages from server/client

[sebasblancogonz]

When sending a message throgh socket.io-client or socket.io, the listener won't receive any message. E.g: On the client project, when adding a new todo, I send a message to the Socket with "socket.io.emit('todoAdded', todo)" but my server project, listening with "req.app.io.on('todoAdded', todo => {})" won't work. Both libraries are listening to the port 3000, this is the port where the server is running.