Gradient problem with object - (Illustrator 26.3 Windows)

Hi everyone !
Glad to post my first issue on the platform.

I ask for your help, cause I fail to find the solution.

In fact, i created an object (i working on this tutorial where i'm stop at 4 minutes) on which I selected a color, and when I want to "Create a gradient mesh" [Object] the gradient is only black and white. However, my menu shows me that the gradient is a colorful gradient (as you can see on the picture).

I absolutely don't know hot to fix it, so there are a lot of frustration, because i just begening to use this amazing software.

Thanks a lot for your response, and have a wonderfull day 🙂
Simon
(sorry for my bad english)