I use my fingerprint to attempt to log in, but the spinner just spins and a file is downloaded to my Download folder with the title icloud.developer.apple.com with zero bytes. I've cleared cookies and cache, but it doesn't help. I can get to CloudKit Dashboard via Xcode in the Signings and Capabilities tab, but I never had to do it this way. I've been doing it via the Mac.
Cannot Log Into CloudKit Dashboard Using My Mac
Never mind. I was using a link that no longer worked. I have updated to the correct link and I can now get on without any problem.