Shelly Dimmer + light turn off above 40%

Hi all,

Last week, i installed the shelly Dimmer at home. There was no neutral wire, so i put one.

The shelly dimmer works, but i can only dim from 0% to 40%, if i go higher, the light turn off, after some time, the shelly dimmer is offline.

Any idea what this could be?

Dimmer is connected to 8 Led GU10 lights from Phillips (4.2 watt dimmable).

Yes, several times.

One time it does a callibration, so you see the light dimmed low and going higher. Another time, calibration is failing so i have to reset the device.

How long does a callibration take? If the led lights don't react, do i have to wait,