Make sure there's nothing in the coin trap (if it has one). After doing that, try resetting it by turning it off, unplugging the machine and turning off the circuit breaker. Then you hold down the start button for 5 seconds to drain the power. After that, plug it back in and flip the circuit breaker. It's like rebooting your computer, resetting the washing machine fixes many problems. It's not a hard task to reset the machine, but I find it annoying that it needs done in the first place.