If you are using a Dymo LabelWriter™ 4XL please see these specific instructions.
As there are many types of printers, it is very difficult for us to provide a catch-all solution. If you are having difficulties, please get in touch with us so we can further investigate your configuration and walk you through the troubleshooting.
Remember, to get printing labels right away, you can always click the "Download" link to open a PDF version of the shipping label. These labels can be printed on most desktop printers. Just be sure that you have installed and configured your desktop printer for your computer.