Did you go set up a proxy connection in LW's settings? I presume you'd need to do this I don't know. Go to LW's menu bar, Tools>Options>Advanced>Proxies

Also, I'd recommend using different ports for each one to connect & listen through. Tools>Options>Advanced>Firewall
You may need to adjust the computer firewall if it uses a port in its setting.

Try port 64049 for the 2nd computer.

Are you using UPnP or manual port forwarding for your modem/router? If manually port forwarded, then you'll definitely need to use a different port to connect thru. If using UPnP, then port listening should be different if possible.