Why does the printer keep printing the same labels continuously?

Reason: The printer didn't recognize the label size correctly 

It is most likely because the printer hasn’t learned your label’s properties, and this is usually followed by a blinking red light. 

(1) Turn the printer off and unplug the USB cable, which can clear any pending print jobs. 

(2) Turn on the printer and load labels from the back. Press the feed button and hold on until you hear one beep, and then release it to run automatic label identification. 

(3) When you see a green light, reconnect the USB cable and try your print again.