If the zebra printer keeps printing a blank label in-between the correct labels, there can be two reasons to this.
Recalibrating the printer.
This guide will cover the Zebra GK420d printer. If don’t use this printer, look up in the printer documentation how to recalibrate it.
Hold down the front button.
When the LED on the left have blinked rapidly twice let go off the button. The printer will now calibrate.
Checking the label length.
When the label settings are set longer than the actual label, the printer will split label up in two.
If you are using the Webshipper labels, see this guide.
If you are using another label format see below.
102 x 152,4
Standard: (Post Danmak)
192 x 192