The print bed is empty! There’s no filament coming out of the print-head? The nozzle is clogged by carbonized material from previous print processes. 

  • Note: If the nozzle is clogged, clean it according to the printer manufacturer’s instructions.

There is a problem with the feeder. The feeder motor may be defective, the pressure the feeder puts on the filament is too low or the filament has ground. If the motor is defective, have it replaced.
  •  Note: Consult the printer’s documentation to see how and where to change the pressure settings – and check whether the settings are correct. If the filament has ground down, replace it.