[ValidateApp | INFO] Validating '/home/jovyan/work/submitted/courseraLearner/W2A2/Logistic_Regression_with_a_Neural_Network_mindset.ipynb' [ValidateApp | INFO] Executing notebook with kernel: python3 Success! Your notebook passes all the tests

That most likely means there is something damaged in your notebook that the grader depends on. The first thing to try is to get a clean copy of the notebook (see the relevant topic on the FAQ Thread) and then carefully “copy/paste” over just your solution code from the “YOUR CODE HERE” segments. Then save, confirm that the tests in the notebook still pass and try the submit again.

Let us know if that helps or not!