Your Roon Server is an earlier build - version 2.59. So your issue is being caused by an incompatibility between Roon clients version 2.60 and earlier versions of Roon Server. See:
Roon Bridge 2.60 (build 1501) Production with EA Roon Server - Early Access - Roon Labs Community
Either update your Roon Server to version 2.60 (Production) or, if you are running Early Access builds of Roon Server, wait until Roon Labs release a new Early Access version. Roon Labs said that they hoped to release the new version last Friday, but apparently it’s still stuck in QA testing.