The first 3 Command & Conquer titles are "Freeware". Tiberian Dawn, Red Alert 1 and Tiberian Sun were released to the public for free with no licence to them (GPL3, MIT...).
I'm not sure under which license CNC Retro would be. (Public Domain??)
I can't hardly say what the issue was. We lost power for about an hour and when it came back I was able to boot and connect like there never was an issue.
I'd suggest rebooting your router if you have a similar issue and if that doesn't work reboot your PC.
Since I changed to the main Wi-Fi network in my house, I've just settled to leave it this way. I've managed to access my recalbox via IP and via http://recalbox.local/ on the subnet.
I don't know how this failed, and worked. It's just the way things go.
I don't think I'm going to have success on my encrypted drive problem, so I'll start a new topic about that.