Alright so, I've been having trouble with my own smash connectivity because I just recently moved to my dorm in college and nintendo 3ds' aren't compatible with their password system. I may be able to smash again when I get the Wii u version but not with the 3ds version unfortunately. :c
EDIT: Good news, the wii u version that I got for my birthday appears to work fine with a wired connection. So I will be able to smash using the wii u version at most while I'm at college. ^^