Wiring water level probe with Shelly Uni Plus

Hello, I have a problem wiring my hydrostatic probe with the Shelly uni plus. I need to get the tension (Voltage) of the probe. There is manual with the probe so I’m confused.

The probe comes with three wires, a red, a green and a yellow.

At the moment I have this setup:

Probe: red wire > with > Shelly red wire (+Neutral)
Probe, green > Shelly, green, black (+ground)
Probe, yellow > Shelly, white

The Shelly works and is sending 0 data with Power and Energy (both I don’t need), but nothing about Voltage.

Thank you for your help!