C1 W1 Assignment - Grading Failed

One possibility is that there is something damaged about the structure of your notebook that the grader depends on. In order to eliminate that possibility, my suggestion would be to get a clean copy and then very carefully “copy/paste” over just your solution code from the “YOUR CODE HERE” sections. Then try submitting again.

Here’s a thread from DLS that explains how to get a clean copy. The material is not DLS specific.