Why I printed many blank labels?

Please confirm if the label loaded upside down. Correct installation as below.

(1) Ensure your labels are "Direct Thermal" labels, 4 x 6 inches label is highly recommended.
(2) If above are correct, but the printer still print blank labels or the label cannot be completely printed. [We need to reset the printer and get the printer to re-identify label size again.]
(3) Pull out the USB cable and restart the printer; Press FEED button and hold on;
(4) Release your finger when you hear five "Di" sound.
Then, you will hear another one long "Di" sound, which means the printer was reset.
(5) Then, we can set the printer to learn label size.
Turn on the printer;
(6) Press FEED button and hold on; Release your finger when you hear one "Di" sound.

Then, the printer will "know" the label size and will not print blank label or incompletely.