[2020] Impossible to change the skin of car

Hi, i have access club and i can't change the skin of my car again. I don't no why. When I try to change it, always gives me the same one. I can't go back to the basic skin. I've already tried to reinstall the game, I've already deleted the Trackmania folder that contains the game's configs. Every time I try, he always gives me the same skin. The skin that comes back each time and a skin that I had downloaded in the game.
Thank you.