Currently if there is some file matching criteria error, the rename files feature does not work. Solution is to remove/delete the files that failed at file matching, go to previous step and come back to this step. Then the rename files feature work again.
This process is not clear and some on text or tool tip would be appreciated.
Another option to cancel the file upload instead of proceeding could be beneficial. If we close the window at this stage, it will just add the files with the original file name and then may need to be deleted (one-by-one) which is a separate issue.