Solution 1:
The tank may have been placed incorrectly. The tank has a magnetic mechanism which enables the machine to detect whether the tank is inside the unit or placed correctly.  

Please remove the tank and try it in another direction or make sure the handle is facing the right way. 

Please click the link below to watch the video:

How to properly insert tank

Solution 2: 

The float might have been fitted on upside down. Remove the tank lid and flip it back around to fix the issue. See image below: