Thank you for posting. This might be a build parity issue; diagnostics indicate that your Roon Server machine is still hosting Roon build 1671, but ARC is on the most recent version. There have been recent features added to the home page in Roon and ARC that likely can’t sync without an updated server here.
Please navigate to Settings → About in Roon itself and follow the prompts to update. Reinstalling the server will also bump to the latest version (ensure you have a Backup of Roon first, for due diligence).
We’ll watch for your reply and move from there. Thanks!