Tips and Tricks to Calibrating your ZD621R Printer
When experiencing voids, changing label size, or if the printer is skipping labels, you should stop and calibrate your printer.
You can calibrate your printer directly by going to the web backend and clicking your account name at the top-right of the page, then Printers; then selecting your printer in the list and clicking "Calibrate Printer".
You may also calibrate your printer directly from the printer itself. Here is a video outlining the process of calibrating the printer manually.