Hi @dand5,
Thanks for reaching out to us to ask about this issue. One of 2 things is likely going on here.
This could be a firewall issue. Please make sure Roon, RoonServer, and RAATServer are allowed through your firewall.
This could be an issue with RAATServer itself. You can follow the below steps to install a fresh copy of RAATServer. Please be aware that doing this will wipe any custom DSP you have set up so make sure you make a backup first.