What if UPnP forwards to the wrong IP with multiple network cards?
This can happen when you have more than one network adapter set up and in use on your computer. DC++ assumes the first network adapter is the one you’re using to connect to the Internet and gets the local IP from that. To change the order of your network adapters, follow the steps listed in this Microsoft article: How to change the binding order of network adapters. Make sure the adapter you’re using to connect to the Internet is on top.