After looking at your notebook, indeed you are passing all the tests, but for exercise 5, your code cell is running into an error (even though later you pass the test). Passing the tests is not all, you have to make sure your notebook is not running into errors anywhere. Otherwise it will also give an error to the grader as you have seen.
The reason that the cell gives an error is because you introduced an extra bit of code in it and added get_llm_response(prompt). This is neither required nor is part of the instructions of that exercise.
The instructions of the assignments clearly mention to not add extra code and only implement the code which you have been asked to.
Remove that and you shall see you pass all the tests.