Homey Pro cannot find any device on my CCU3

Hi everyone,
i have a Homey Pro and want to connect my homematic IP devices with homey. I have a CCU3 in my local network, installed the homatic-app and started the assistant. my ccu3 was found successfully but it cannot find any device on it.

i have re-installed the app already, added new devices to my ccu3 - no success when trying to bring them to homey.

I have no idea what to do