What happens when you try to open the PDF files? For example:

• Firefox displays an error message
• Firefox automatically saves the file instead
• Firefox displays a dialog that doesn't have the PDF-specific choices
• Something else...

Nothing. The files appear shaded in light gray so I cannot click and open them.

See:

• https://support.mozilla.org/en-US/kb/view-pdf-files-firefox-or-choose-another-viewer

Nothing. The files appear shaded in light gray so I cannot click and open them.

Hmm, what kind of site? Like Google Drive, OneDrive, Dropbox, etc.? Or just typical websites that have article links?

Typical websites that have article links. Thank you

Like this? https://www.jeffersonscher.com/scu/2009/a/2007FinalExam-S1-ModelAnswer.pdf

In the default configuration, that should display in a tab, using the built-in PDF viewer. What happens on yours?

This worked thank you very much!!