It keeps outputting blanks labels or blinking red light continually

It is most that the printer has not learned your label's properties.

Please follow the steps below to fix problems:

1. Long press and hold the green feeder button until the printer beeps 4 times to reset the printer.

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2. Switch off the printer by the button on its back and switch on to start the printer again. 

3. Open its cover and reload your thermal labels again, close the cover.

4. Press and hold the green feeder button until the printer beeps one time to identify and calibrate your labels. You should see your label moving back and forth and stopping at the correct tear-off point. 

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5. Try your print and it should print perfectly moving forward until you see a green light.