Verify you have water pressure to the washer, turn the water supply off and remove the hoses from the washer check the the fill hoses for stopped up filter screens (some hoses have screens in them). Check the screens on the water inlet valve of the washer, sometimes mineral deposits can build up slowing the water. Hold the hoses over the tub of the washer and turn them on to verify pressure from each hose.
If you did not find any blockage then you will need to replace the water inlet valve on the washer.
Part #: 422245 - Washer Inlet Valve