Have you tried changing the DNS server assigned in the router settings? If your network is relying on the default or ISP-provided DNS server, try using Cloudlfare (1.1.1.1) instead.
Double-check that Roon’s processes are safelisted in the Windows Defender firewall. Clear the cookies in the default browser.
Then, logout of Qobuz using their account webpage. Restart RoonServer and try again.