Sorry that the grader can’t give more specific feedback. The type of bug to look for is as Saif suggested: some way in which you have hard-coded things to match the test cases in the notebook, but which fails in general with different arguments. E.g. it could be assumptions about the shapes of the objects or referencing the global variables that happen to get passed as arguments directly, instead of through their parameters in the function body.
If you can’t figure it out based on the above hints, then we’ll need to examine your code.