I apologize if this is the incorrect forum to post this. I've done some googling, and this error is apparently for when the region of your 3DS and NNID do not match. My 3DS is from the US, and my NNID has the region set to US as well. If it means anything, in Settings -> Other Settings -> Profile -> Region settings, the region is set to the US as well. The only fix I have found involved three SD cards with different regions set for the EmuNAND. My 3DS is on 10.3.0-28U, so EmuNAND is out of the question. I've reformatted my 3DS a few times to see if that would fix it, but it did not. Any ideas?