SEN0208 led blink once and that's all

Hi,

I don't want to let the device power 24/7 as I need to monitor the water in my external tank only a few times per day.

I've been able to control the SEN0208 power using an arduino nano GPIO some time ago, then I've tried other things on this arduino letting the SEN0208 unused but plugged in.

From now when I power on the SEN0208 directly on +5V or +3.3V the led turn ON then OFF very quickly and device does not answer anymore to trigger.

Currently SEN0208 never get out from my desk.

Any idea about what can cause this?

Thanks