The fault may be due to a defective solenoid valve, and this must therefore be replaced. Purchase a solenoid valve for your washing machine here.

Check to see if the water that goes in to the machine is clean. If it is not, it is coming from the outlet hose. This typically happens by the outlet hose being connected to the kitchen sink tail piece/plumbing of a kitchen sink, where there are issues with a blocked drain. Problems can also occur, if the outlet hose is wrongly mounted on the kitchen sink tail piece/plumbing. For correct mounting the hose must have a slight bend upwards, so the water cannot run down and into the washing machine.

Therefore, if the water in the washing machine is not clean, you must both fit the drain hose correctly at the same time as replacing the solenoid valve. Correct installation of the drain hose can be done, for example, by purchasing a hose hanger for the drain hose.