A Model number might help.

Check the overflow switch, the switch should be activated re:float down.

With a meter check across the water valve it should have 120 volts when the unit is in the fill part of the cycle.

If it does have voltage then either the valve is toast or it's screen filter is plugged.
Remove the valve and check/clean the screen filter built into it's input side. Do not permanently remove this screen as it is there to keep crud out of the valve which could hold it open and cause a flood.
If the screen is clean then the valve is toast.
This assumes that there is water at the valve.

If there is no voltage check across the valve and float (overflow switch), they are wired in series.
If you have voltage then the float is either jammed in the up position due to crud or the switch is toast.

If you have no voltage then you probably have a timer problem.