Are you using the Download button on the toolbar of the builtin Firefox PDF Viewer or don't you get this viewer at all and you get immediately the download dialog ?

What is the current action for Portable Document Format (PDF) files?

• Options/Preferences -> General -> Applications
• https://support.mozilla.org/en-US/kb/change-firefox-behavior-when-open-file

See also:

• https://support.mozilla.org/en-US/kb/view-pdf-files-firefox
• https://support.mozilla.org/en-US/kb/disable-built-pdf-viewer-and-use-another-viewer

PDF action is always ask. The download seems to indicate that 11mb of 90mb downloaded, then it continues to cycle, now over an hour, with no further action. In addition to Rdge and Android, it also works in Safari and Firefox on iphone.

It is possible that (anti-virus) security software is causing the problem.

Try to disable security software temporarily to see if that makes a difference.

I tried that as well. It seems to be downloading very slowly. It has taken over an hour to download 37mb of 90. I have downloaded another similar file from a different site in a minute, and from this site on other devices in a minute. Very strange.

Are you possibly using a proxy or VPN ?

You can check the connection settings.

• Options/Preferences -> General -> Network: Connection -> Settings

If you do not need to use a proxy to connect to internet then try to select "No Proxy" if "Use the system proxy settings" or one of the others do not work properly.

See "Firefox connection settings":

• https://support.mozilla.org/en-US/kb/firefox-cant-load-websites-other-browsers-can