Please see here: Tidal login issue : non-200 status code from Tidal [Tidal Side Issue - Now Resolved] - #146
Your original post coincided with a known Tidal service outage that they have by now mostly resolved. You may have additional issues specific to your setup.
Note that if you’ve favorited content from the Tidal web player, it will not sync via the same pathway as the Tidal app and these changes may not appear in Roon.
Additionally, I’d verify that your DNS server is reliable in your router web administration. We usually recommend Cloudflare DNS, Quad9 or Google DNS based on user experience here.