The steps below are listed in order of complexity. Many printer issues can be resolved in a couple simple steps.
Restart your computer. A fresh start forces the computer to check and re-connect files and programs after installing updates or reconnecting your printer.
Try printing from a different browser. If you’re using Safari, for instance, try a test print from Chrome.
If printing works on the second browser, then check that java is enabled and your pop-up blocker is turned off. You’ll also want to clear your cache and cookies.
If you’re still experiencing issues with your printer, please check the following
Check the printer wires and USB cable to be sure that the printer is plugged in, turned on, and connected to your computer.
Check that the paper is installed correctly. It needs to be situated so that the end of the paper is rolling out from under, and not over the top of the roll.
Check you’re using 80mm thermal paper.
Make sure that the printer actually works by performing this Feed test.
Check that the printer is plugged directly into the computer you’re using. Receipt printers cannot be shared.
Close software programs that use USB ports (like iTunes).
Temporarily disable any antivirus or spyware programs running in the background.
Open your print settings, and verify your printer is set as the default printer.
Check that you have the latest Java version installed at www.java.com/verify, and that Java is enabled for your browser.
Try using a different browser.