When all the lights are flashing together, turn the printer power OFF, wait 5 seconds and then turn the printer power ON again.
If the error continues, disconnect the interface cable from the back of the printer and use the following steps to reset the printer:
Turn the printer off.
Press and hold the Go button on the front of the printer, at the same time turn the printer power on.
When the Toner light is on by itself, release the Go button.
Push and hold the Go button again, release the Go button when the Paper light is on by itself.
If this does not clear the problem, consult your dealer or your authorized service representative.