You still can run the machine right?
I think it's the earth leakage monitor. Inside the control cabinet you will find a yellow box (F7 is marked on it) if one of the yellow lights came on, just press the test/ reset button briefly. Then it should be fine. But if you're getting the error again and again, you have to check the wiring for earth leakage. Or else, the monitor itself may be faulty.
