Send to email not working in PDFCreator 5.0.2

A few users within the company have reported a sudden stop in the ability to use the email button in PDFCreator. When clicking the button nothing happens. This is only affecting a handful of users, and some are still able to use the function properly. This leads me to believe that it may be an issue with the specific install.

I have uninstalled and reinstalled the program, however this had no success in fixing the issue. I have been searching the forums for a possible solution but am yet to find anything that will work.

If someone could offer assistance that would be great.

also didn't help: reinstall email,
windows settings- set thunderbird to standard programm
reinstall pdf creator

last time I had this issue, I had to do a backup restore of the whole PC.