Please follow the steps below:
1. If you are using the device for the first time or if it hasn't been used for a long time, switch on the power mode for about 3 minutes.
2. Remove the clean water bucket and clean the pipe under the bucket in case of blockage.
3. After clearing the blockage, fill the pipe with water and switch on the self-cleaning mode to see if the water goes down.
4. If it does and the problem persists, the clean water sensor may be broken.