Permission denied: WIA1/Building_a_Recurrent_Neural_Network Step_by_Step.ipynb

We literally have no way to know that. It is in the hands of the course staff and Coursera. Apparently Coursera has not yet reported anything to the course staff.

FWIW you can protect yourself against the loss of work: just download the notebook by doing “File → Download as notebook (ipynb)” before you submit or save anything. That is also documented on the DLS FAQ Thread along with ways to download all the files associated with the assignments, not just the notebook.