What do I do when error code E:15 appears on the display?

Error code E:15 (shown as ':‚‰' on the display) indicates a water supply issue — check if the supply hose is kinked, if the water supply is turned off, or if the water supply line is clogged. Straighten any kinked hoses, turn on the water supply, or unclog the water line to resolve the issue. (Page 43)