Please help: trying to recover saved file

So I am doing this work for an assignment, and today my saved work decided to bring up an error page, stating the the server my work was on no longer exists. I am currently deliberately trying to recover my work, before due in which is in 3 days from this posts release. I am am currently receiving this error:

Unreadable Notebook: N:\Assignment+work.ipynb AttributeError(‘cells’)

if anyone can help me, ill be massively in your dept.