Run the Auto Clean cycle. The message activates after about 60 brews as a maintenance reminder.
Combine 6 cups white vinegar and 4 cups cold water in the carafe, pour it into the water reservoir, place the empty carafe on the plate, then press and hold the On/Off button for 4 seconds. The cycle takes 45-60 minutes and shuts off automatically. Afterwards, brew a pot of fresh water before making coffee.