DIAGNOSIS The inlet water valves on the back of the washer are probably clogged with sediment or mineral scale. Yeah, this one's common, especially if you have hard water.
FIX Unplug the washer and turn off both hot and cold water supply valves. Disconnect the fill hoses from the washer. Check the small mesh screens inside the water valve inlets on the machine—they're tiny filters. Use needle-nose pliers to gently pull them out. Rinse them clean under a faucet and poke out any debris. Reinstall the screens, reconnect the hoses, turn the water back on slowly, and check for leaks before plugging it in.
IF THAT DIDN'T WORK One of the solenoid coils on the water valves could be failing, not opening fully. You can sometimes feel a slight hum/vibration from a good coil when the washer is calling for water. A dead coil won't hum at all.
HEADS UP Don't run the washer without those inlet screens. They protect the valves from bigger debris. If they're too damaged to reinstall, you need to order new ones specific to the model.