Check water supply, this could sound crazy but sometimes the water pressure could be cut off accidentally or a valve stops working. Another cause could be from a bad hose that has clogged up and stopped water flow to the washer. Next step to disconnect the hoses to see if the lint screen is clogged with gunk and other sediments. This can happen to either hot or cold lines and there is usually a filter connected to the inlet valve and these valves sometimes get blocked. This is an easy fix, just turn off the water supply and disconnect the hoses and remove anything you see blocking the flow. If these simple steps do not get the washer up and running again then there could be a part that has failed.
The three most common parts to check in this case are: Bad lid switch, this is a safety switch that prevents the washer from running when the door is open. If the switch is bad the washer will think the door is ajar and will not start a cycle. Bad water level switch, this switch tells the washer to shut off water when the level is met. If this switch goes bad it could tell the machine not to fill. Bad water inlet valve, last but maybe the most common. This part is usually the culprit in this situation and is relatively easy to change out. If you are comfortable doing this repair just order the part online and install it. If not, you can always call On Premise Appliance Repair to get this repair done!