Do you have the domain registered in DNS in your network settings? You should be able to ping your FQDN from the command line successfully.
You say you can't get node.js to listen to it, but your original post mentioned that you didn't have the domain entered into the allowed list (I assume in your portal settings). You can send me a direct message if you want to see if I can provide any more help with specifics (like domain names or IP addresses) that you don't want to post here.