Hey there!

I would recommend you to do the following.

1) Check your print settings on your computer

If it still does not work see the link below on ways to solve printing problems on Firefox:

https://support.mozilla.org/en-US/kb/fix-printing-problems-firefox

Hope I helped!

Kind regards,

Bithiah

Do you mean that you can't print a PDF file you downloaded from internet ?

Can you open such a downloaded PDF file in a Firefox tab and pint the file that way or open the file in Firefox instead of saving the file to your computer ?

I thank Bithia and Cor-el for their replies .

The problem was in my computer settings, not Firefox.

Thanks again for your help