Water line frozen

Generally the fill tube will freeze due to air getting into the water system or having poor water pressure from your house. Make sure you have good water pressure to the house and that the filter isn’t expired yet. If the water pressure reduces, the water will go through the fill tube too slow and freeze solid over time. Other than that, when you replace the filter–make sure to flush out a few gallons of water to expel al the air in the system so that you don’t get dripping through the fill tube which can freeze it up.