Hello info586,
Don't worry! I've got you covered and can help you with this. I know how important it is to make sure your customers receive their invoices. The printing option, which uses a PDF viewer, is great for giving them a hard copy to hang onto.
Since it's not working, I suspect you may be having some browser or app trouble. One great way to take care of this is by clearing the cache to ensure temporary Internet files aren't causing problems for you. This article goes over how to do that and includes a link that I encourage you to review to make sure you're using a supported browser and system: How do I clear my cache and temporary Internet files?
The next thing to check for, especially if you're using a browser, is any pop up or ad blocker that might be preventing the print window from launching. Pop up and ad blockers are typically added through browser extensions, but can also be a part of firewall set up as well. If you're not sure how to check for these, I recommend searching Google to learn how to find out this info for your browser or operating system.
Lastly, try restarting the computer. I know it sounds basic, but this can sometimes kick things back into gear and get you back in working order.
Give me a shout if you need anything else!
