Hue Dimmer stop sending informations

Hi guys.

I have a SmartHome based on Apple HomeKit and started weeks ago to bring everything into Node-Red. So I‘m a newbie.
Most of the thongs are running quite well, but I got problems with my Hue Dimmer V1. I did a factory reset with one of them, so that I‘m sure it isn‘t used by HomeKit. When I press a bitton afzer developing I get the debug for initial_press and release. Sometimes I can press buttons dor several times and I get all the messages. Bit for some reason after a while it stops. Hue button says „waiting…“ and I don‘t get any messages in the debug anymore.
For testing I connected the button directly with nothing upfront or behinde to the debug-node to check this, still same.
I use the huemagic node.

Thanks for your help.
Nico