Reset age limit on Nintendo 3DS?

I want to reset the age limit on my Nintendo 3DS, but somehow it doesn't work, because every time I go to the age limit I get this message.

How old are you?

Of legal age

Then you should be able to read. Are you online and followed the steps there?

I followed the steps! I closed the settings, was then connected to the internet and opened the settings again and wanted to reset it. But came this ad again!

If you're unlucky, this online service simply doesn't exist anymore. Maybe googling afterwards.

I already have it.