I need help. I have been accessing normally my Samsung Galaxy S4 via the Camera (PTP) USB Connection, until just a few minutes ago that I can no longer access it at all. When viewing it in my phone using the Files folder, I can see all of my files, yet when I plug it again via the USB, I am unable to view any of them. All the folders show, but each folder shows no items. What could be the problem here? How can I get this back to normal? Please help. Thank you!