Your ROCK shows early access OS shows Version 1.0 build 259 and software version 2.47 build 1506, the latest releases are version OS is 2.1 build 270 and software version is 2.49 build 1526.
I would make sure your clients are, either on the same train and version/build as your server. Or update all of them (clients and servers) to the latest version/build.
You may need to reinstall ROCK and clients to get this working (it may be an opportunity to update to UEFI in the NUC Bios if you have not already, this is required to get the latest Roon features):