Enter the Nintendo WFC Settings menu, which can be found in any WFC-enabled game.
Select "Nintendo Wi-Fi Connection Settings".
Set up a new connection if you haven't already done so, then select the connection slot you wish to use.
Scroll down and set "Auto-obtain DNS" to "No", then set Primary DNS to
18.104.22.168and Secondary DNS to
0.0.0.0. Select "OK" to confirm.