DIAGNOSIS This is almost always a tape cartridge problem. The feed mechanism is grinding against the tape spool because the cartridge isn't seated perfectly, or the tape is jammed at the cutting blade.
FIX Turn the machine off. Open the tape compartment door and remove the tape cartridge. Look inside the empty compartment—check for any tiny bits of torn tape or adhesive stuck around the silver print head roller or the black plastic feed gears. Use tweezers to gently pick any debris out. Now, re-insert the tape cartridge. You should hear and feel a definitive *click* when it's fully home. Close the door firmly. Turn it on and try a test print.
IF THAT DIDN'T WORK The issue might be with that specific tape cartridge. Try a different one if you have it. Also, ensure you're using the correct tape type (like D30-compatible) and that the tape width guide on the cartridge matches the setting you selected in the app.
HEADS UP Never force the tape cartridge in or try to print while you hear grinding. That's how you strip the plastic gears. If the gears look damaged, the mechanism itself is likely toast and needs replacement.