Grading Error While Submitting the Notebook

Most of the folks listening here cannot look at your notebooks directly. Only the course staff can do that and they are (generally) too busy to hang out here.

That error most likely means that something is damaged in the parts of your notebook structure and metadata that the grader depends on. The first thing to try is to get a clean copy of the notebook and then very carefully “copy/paste” over just your completed code segments and see if that fixes the problem. There are instructions for how to do that on this DLS topic. The same mechanisms should work in all the specializations, since it’s just using Coursera notebook features, but let me know if you can’t see the thread.