A clean uninstall of the AdagioPDF nova printer driver, program and registry did not make the trick either but I finally made it work.

There was no issue printing using the Administrator user.

Therefore, the issue was in the user profile. It might be a temp file or something else in the registry.
Changed the default printer (In our case, the user was the only one having this printer as default printer (RICOH Aficio MP C3001 PCL 5c) and run Adagio with Run as Administrator. Printed a report to .PDF. I thought, this works because it is using the Administrator profile and that profile doesn't have the printer driver installed. However, when I tried again without Run as Administrator, it sent the report to .PDF. We put back the default printer, and still works.

Using Run as Administrator with the user profile might have deleted whatever was causing the issue.

This site was recently upgraded. For the ones that suddenly stopped working; more likely the reason was a windows update or the antivirus update.