Well, I tried copying the mp3's using the Xbox One yesterday, and while the OST did seemingly set up a server to connect to, I couldn't connect to it from my PC.

I then tried the PS4, and that one worked just fine. The difference is that the PS4 had a non-standard port (9999) to connect to, the Xbox One didn't mention any specific port. Might be you have to connect to port 9999 on the Xbox One as well.