I want to send a ban appeal, what's an authentication PIN?

[CyberStarLight]

I'm trying to ban appeal on this page: https://appeals.ccgn.co/

But after entering my username It says:
"Please enter your authentication PIN given to you in Minecraft (Need help?)"

I don't know what an "authentication PIN" is and clicking on "Need help?" does nothing at all..

What am I supposed to write in the textbox?

 

[Story]

If you log onto cubecraft you should recieve a code, input that into the appeal.

 

[CyberStarLight]

If you log onto cubecraft you should recieve a code, input that into the appeal.

Thanks Drew! I logged in and got the number.