Sure. You can use a different server for Jot Messenger. The only problem with that is if you do not have access to that server yourself, all you can do is just ensure you have the right URL in the Messenger module. It would be up to whoever owns that server to make sure the Cert is valid (if using HTTPS), the app.js is running, and if port 5433 is indeed open for Jot Messenger. So to answer your question, if you are being told to use the IP address, port 5443, then what you have there would be correct.