I have solved (partially) the issue.
Solution #1
Change the format from PDF to HTML
Solution #2
Go to plugin settings -> Status -> Click on “Create a new temp folder”
Go to plugin settings -> General -> Select “open the pdf in a new tab of browser” on “How would you view the pdf?”
If I use the 2nd solution I can print pdf files.
PS: I have translated from Italian to English the plugin settings text