So we can better assist you, please provide a brief description of your current setup using this link as a guide.
Make sure to describe your network configuration/topology, including any networking hardware currently in use, so we can have a clear understanding of how your devices are communicating.
Is there any change if you reboot the Core?
Can you also try completely signing out of TIDAL in Roon and signing back in?
I’m having similar issue. Latest roon version 1.8 build 764. Restart roon, login logout Tidal. Reinstall the roon itself…even restart the actual roon nucleus itself. Run direct from Tidal app is okay, so clearly it’s not Tidal issue. All was working before update too. I also try to disable the tidal service in roon and enable again but no success…