A user can't upload readable PDFs. She can view PDFs, email them to other people who are able to view them, create PDFs, etc, but when she uploads a PDF to Canvas the PDF is listed but the icon is plain white instead of a white background with the Acrobat logo. This happens with PDFs she creates as well as with PDFs created on other machines. It happens in all three main browsers. When the PDF is selected, an error message says the PDF can't be accessed. This user can add the same PDFs to Box and view them. Anyone have any ideas?