bitfactory

Good point. The Osrams were sold as dimmable but according to the online specs you are right. I just connected the COB Led directly to the dimmer (so no long wiring inbetween) and there calibration was possible now. I'll try to trace this futher an report then.

Tried with these (+ more which i do not have at hand right now) -> COB LED 220-240v 7.5w (no name from a local store here -> c-light) Osram ac03076 2700k 50/60hz 52mA 7w 220-240v Osram ac32396 2700k 50/60hz 32mA 4w 220-240v I tried them singular and all together. Same result.

Where did you contact them? Did you open a warranty case for this? Edit: nevermind. I have a different error. Claims "Lights are not dimmable" which is covered in another thread here.

Same problem here. Tried with different light sources. All around 7w and definitely dimmable (worked with Eltako dimmers before). I also tried using just one light and up to 6. No change.