I have two 3DS consoles and two ACNL games going. I would like to make friends on both but only the first DS code shows. When I try to input the second DS code, it tells me to make a new town and a new character, which I have (here on ACC). But the second DS code keeps disappearing. How do I get both DS codes to show on my profile?
The problem is actually with your Wild World and City Folk friend codes. You have them filled out on your profile, but you've deleted your WW/CF towns from your "ACC Towns" section. So, when you click Save on the Friend Code editor, the page realizes you have WW & CF friend codes, but no towns, and gives the error. It's very confusing, but it's happened before.
To resolve it, just remove your friend codes for Wild World and City Folk from the Friend Code editor, and you'll be able to add your other 3DS codes.