Valid registered users cannot view article PDFs: they are redirected to the main page instead

Hello, non-admin users registered with my site cannot view PDF articles (oddly, full issues appear not to be a problem). When a PDF link is clicked the user is simply redirected back to the index page of the site. I have confirmed that this happens with registered users who have an active subscription, though not with admins.

  1. I do not thing there is a permissions issue. I was able to upload new article PDFs just fine, and I can view them as an admin.
  2. I have tried several different users with differing expiration dates. No difference.
  3. I have tried updating the user information by assigning them a role (Reader). Previously, roles were not required when editing.
  4. The only error that comes up in the console is as follows: “Empty string passed to getElementById().”
  5. Finally, I also tried disabling the PDF.JS PDF Viewer plugin. That had no impact on the problem.

I thought this issue was related to the Unlocking/Locking of PDF links because, as an admin, the PDF links show a lock even though I’m logged in. However, that is likely just because my user does not have an active subscription.

Any help would be sincerely appreciated.

P.S. I’m updating to 3.1.1.2 now but I already applied the patch so I do not expect it to make any difference.