Sharp copier m550n

I have a problem with the sharp photocopy AR-m550n it is blinking L4-03

My copier is telling to change cartridge and I already have filed the toner into the drum but the message is not going away. Please help

L4-03 is a lock of the fusing motor. It's likely you need to have the fuser rebuilt. You can try resetting the error by turning off the main power switch (located behind the front door under a little plastic cover) and back on. It's likely the error will come back. There's a cleaning screen on the lower fuser roller which gets gummed up with toner and sticks to the lower fuser roller causing it to seize and the motor not to be able to turn causing the L4-03.