@garfunkel
Don't know this solution helps for PC version, but for Pi it works fine most time:
Change wifi region from "US" to some european value (FR, DE, AT,...) in recalbox.conf
May I ask what you can tell about running recalbox on such NUC in general? Is it working well? Is it possible to emulate GameCube and Wii smoothly? I'm sometimes thinking about buying an NUC for emulation, but don't know if it's worth at all...