If your RoboVac L70 Hybrid encounters an issue with the mopping function, the app usually alerts and states the water tank is empty when it is in fact full. 

Please try the following suggestions and verify if the issue can be resolved: 

- Confirm that you did not add any cleaning solution or warm water into the water tank. Please use only cold water. (eufy cleaning solution is not recommended either,  Basic Inquiries about the RoboVac Hard Floor Cleaning Solution)

- Make sure the water tank is sealed and the water tank and the dust collector is properly installed. Check to make sure there is no blockage between the part and the vacuum. Clean the connectors and interface. 

- If this does not help, please slightly lift/press the water tank and dust collector. 

You can try using a pin or needle and insert it in the water pump connector to ensure the water passage is not blocked. Make sure the mopping cloth is wet before installing it under the vacuum to start mopping.

Send us pictures of the water dispensers (see the attached).
 

If the issue still persists, please contact us for further assistance.