I'm also trying to figure that out :{

restart your wii, close and reopen splatoon, delete the shared data in system settings, or just wait. give all of them a try i guess.

every time before you open splatoon, you gotta go to system settings, data and management, and delete shared data for splatoon (dont worry, doesn't do anything to your save.) if you use inkay, this works every time. if you use SSL, it may take a few attempts, but works eventually