For the longest time, I didn’t know there was an organisation behind NaNoWriMo. I always thought it was a challenge based around a month like inktober or a new year resolution but for November. (Although, looking into it, there's also an organization for inktober.)
On the bright side, you can still do a similar challenge next November, but without the official™ NaNoWriMo org. That’s what I did last time, write 50k words for a web novel in a month.