Hi @GIOVANNI_SELGI,
It looks like you have something in your code that is expecting the code to be run on a GPU. When you’re running yourself, this is fine, since the development environment is set up to use a GPU (intentionally, since it’s faster, saving you time). BUT, the grader runs using only a CPU, which is why you see this error only when you submit to the grader.
You can check your code for anywhere that sets device=‘cuda’ (which means to use the GPU). There is one expected place in the Training section where this is set intentionally for when you are training, but you shouldn’t be setting it anywhere else, and you shouldn’t edit that line in any way since the grader needs to be able to find that line and disable it before grading your assignment.
There’s a more detailed explanation about this here: C1W1 Grader Error "Found no NVIDIA driver on your system."