Hey @GabyTM I think what’s probably going on here is that you have Express setting up a listener on the port represented by process.env.PORT and you’re also setting up a server that’s listening to the same port, so you’re basically saying “hey app, listen over here on this port, but also listen over here on the same port” which will result in the error you’re seeing.
I talked about this in some detail in Page cant be found, but in essences you should be able to use
const server = http.createServer(app);
and tell your DBL object to use that server, but you need to make sure that when you start up your Express app you also use server.listen() there instead of app.listen() and that should stop the “Address already in use” error.