Hi, welcome to Just answer
How old is it ?
Do you hear a hum sound from the drain pump as well ?
It is 2 or 3 years old. Yes the hum from the drain pump is there virtually all the time apart from when the machine is first switched on when it starts its normal cycle.
If you have cleaned it completely after taking off the side and top panels...and checked nothing is stuck in there then it is the drain pump that will need replacement