Week 1 Programming Assignment: Convolution Model Application grading error

I’m having an issue with the grader. I’ve completed the assignment and passed the tests at all exercises. When I submit assignment to the grader, it says that nbgrader-part have an error. And gives me zero grade.
I tried to contact the coursera support, but they couldn’t fix the problem.
Any idea what could be wrong?

Just to be sure, have you tried restarting your kernel?

yes, I tried that. also I tried to restart the server

Can you please show us a screenshot of the actual output you get from the grader? Please make sure to click “Show grader output” first.

here it is

It looks like you must have duplicated one of the graded cells or something like that. My suggestion would be to get a clean copy of the notebook (See the DLS FAQ Thread for instructions) and then carefully “copy/paste” over your completed work from your current copy to the new clean copy without changing any of the structure of the notebook.

Then submit again and let us know if that helps.

Or if you can figure out which cell is duplicated, try deleting one of the copies.

that made the job done thanks for your help