Cannot add Paulmann 501.23 bulb

Hi, using the Con Bee II stick I am managing ten devices (Paulmann, IKEA, Hue) already. This works pretty well. However, as a IKEA bulb died I replaced it by Paulmann 501.23. Unfortunately I was not able to add it to the lights, neither by APP, nor by Gateway UI. Tried resetting the bulb, no success either. Three minutes are passing by and no new device is found.
Any help aprecciated