Please explain the problem in detail. What happens? What is/are the exact error message(s) ? Make sure you are not blocking content. [https://support.mozilla.org/en-US/kb/diagnose-firefox-issues-using-troubleshoot-mode Diagnose Firefox issues using Troubleshoot(Safe) Mode] {web link} A small dialog should appear. Click '''Start In Troubleshoot(Safe) Mode''' (not Refresh). Is the problem still there? --------------- https://support.mozilla.org/en-US/kb/enhanced-tracking-protection-firefox-desktop Many site issues can be caused by corrupt cookies or cache. '''Warning ! ! ''' This will log you out of sites you're logged in to. You may also lose any settings for that website. * [https://support.mozilla.org/en-US/kb/delete-cookies-remove-info-websites-stored Delete cookies to remove the information websites have stored on your computer] {web link} * [https://support.mozilla.org/en-US/kb/how-clear-firefox-cache How to clear the Firefox cache] {web link}acking-protection-firefox-desktop

Are you getting the download dialog if you try to open the PDF files or doesn't anything happen ? *https://support.mozilla.org/en-US/kb/view-pdf-files-firefox-or-choose-another-viewer