Maniaplanet Forum

https://imgur.com/euwHeln
I've received one email with the key and my account and I've copied this key to active my account when I paste the key in profile to active, the game show me this messenger. Can someone Help me?!
PS: If I make mistake about grammar I'm so sorry my English work in progress.

For which game did you purchase and receive the key exactly?

Here you are in the forum for Trackmania² series of games, under the hood of Maniaplanet.

But your screenshot is from Trackmania United, where keys for Maniaplanet do not work.
Also the accounts are separate!