Hi @steven_berne,
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.
When this issue occurs, do you see the NAD at all in Roon? Are you receiving any error messages?
Can you verify that both Roon and the NAD are both fully up to date?