DNS exploit not working on a 3DS XL

No matter what I try, it keeps giving me the same error message. I successfully performed the glitch on HeartGold a few weeks back, using a friend’s wifi connection with no password (my provider forced a password). My understanding is that I should be able to do the BW2 exploits using password protected wifi, but this is all I get. Nothing in tutorials I can find is explaining the issue. Can anyone help a homie out?