Mario kart 7 (3ds) error?

Moin, I wanted to play online with a couple of colleagues mario kart 7 on the Nintendo 3ds tonight after years. Now I wanted to "play in" but when I click on online I only get:

Error code: 006-0502

An error has occurred.

Please try again later.

If the problem persists, write down the error code…

I checked online to see what Nintendo Support has to do with it, but they only say something with DNS or something, and that didn't work 🤷♂️

Would be really nice if someone could help me 😃

LG

I believe that Nintendo's online servers have been shut down, because that's exactly how it is with Morio Kart Wii.

OR

Your 3DS is not connected to the internet.

Same issue but the mk7 servers have not shut down and my Internet is fine