My library loads fine. I uninstalled Roon Core and reinstalled, same issue with Tidal not connecting.
It was working fine this am and then stopped working. I can access my library from all devices, but Tidal (via Roon) is telling me to check network. I rebooted my router, no change. I can load the stand alone Tidal app and it works fine.
I don’t think there is anything you, or anyone else, can do about this. It’s an issue on the Roon services side, and we will have to wait until they have fixed it.
If disabling the firewall/antivirus does not help, we have seen users have a better experience in the past if they change their DNS servers to Cloudflare (1.1.1.1), Google (8.8.8.8) or Quad9 (9.9.9.9). I would give that a try and see if it helps.