I bought the game correctly, but I get that error and I can't continue, my pc should work very well due to the requirements, please I need a solution
sounds like you may have a laptop, first post the specifications of your computer and then we'll have a better idea of what can be done.
Open rFactor 2 configuration via steam, then select the right GPU. The configuration program tends to refuse to save settings, so you'll have to do this everytime before you start up the game.
A recent update was said to have fixed (or at least altered) the GPU selection issue for laptops, so the game will automatically pick the more powerful option. We really need more info from the OP on this one.