Ignore this blog if you do not have trouble with your friend code. If I missed a problem, comment.
I can't connect to Nintendo Wi-Fi
Check your internet connection.
Nintendo Wi-Fi still won't work and I'm ready to Rage Quit
Update your DS/DSi/3DS.
This Friend Code is Not Valid!
The person may have started a new game, or the code does not exist. Choose a different friend code.