Node server fails to listen to public IP

I am trying to get my Node.js server to listen to a public IP so that I can access it on a different network than my home network.

I've purchased a domain and used a DNS host - right now I'm using No-IP and have downloaded their client to push my IP to their servers.

When I set the IP on No-IP configuration to my local IP I can use the domain name and hit my server on another computer on my network. But if I change this to my public IP and use the domain, the request hangs for about 10 seconds and then fails. I've set up port forwarding (I believe correctly) and opened inbound / outbound traffic on the port I'm listening to (not 80 right now). I even pulled my firewall completely.

I tried changing server.listen(4444) to server.listen(4444, '0.0.0.0') as I've seen all over the web. But this doesn't work.

Anyone have ideas out there? I feel like maybe my ISP is blocking it somehow? I'm fairly new to networking, so maybe I'm missing something critical?

Thanks!