Hi @Dennis_Remer,
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.
Is there any difference at all in how the microRendu connects to the network compared to the P.S. Audio device? Any different switches or other networking hardware in use for the Rendu?
Are you able to play to this device outside of Roon?
If possible, can you try to connect the Core machine via Ethernet and let us know if there is any difference? As mentioned in our Networking Guide, we recommend using an Ethernet connection for your Core machine whenever possible to avoid potential networking issues.