Hi @Uwe_Groth,
So we can better assist you, please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
Just to verify, this device is showing in Roon but playback isn’t working? Are you receiving any error messages? Are other endpoints working okay?