I think that Roon Labs just silently dropped support for the outdated and insecure SMB protocol version 1 on/for Roon OS. Your Innuos device on the other hand seems to support SMB v1 only (you may want to ask Innuos support for clarification on that).
UPDATE: You can also try and replace the server name (zen) with its IP-Addresss in case there is an issue with name resolution on current Roon OS.