DIAGNOSIS The water pump in the cleaning station isn't delivering enough (or any) water to the pads. This could be due to a setting, an empty tank, or a clog in the system.
FIX First, check the basics in the app. Make sure the mopping water level is set to something other than 'Low' or 'None'. Then, physically check the clean water tank on the station—is it full? If so, remove the robot and look at the mop pad assembly. Detach the pads and the plastic tray they clip onto. You'll see the water outlets. Use a pin or toothpick to gently clear the tiny holes, then run a water-only clean cycle to see if flow resumes.
IF THAT DIDN'T WORK The internal tubing or pump in the station could have a blockage or have failed. Try removing the clean water tank and blowing gently into the tank's outlet port to see if you can clear a blockage (use a clean cloth as a filter). If there's no resistance, the pump might be dead.
HEADS UP Always use the official cleaning solution or plain water. Thick or soapy cleaners will gum up those tiny water channels almost immediately, causing this exact problem.