William A. if you try clicking the link again from the Vercel page does the login work on the second try? I am seeing errors sometimes on the first login attempt but it is working on subsequent attempts. I'll check in with the Vercel team to see if they have some more information about the fail Authentication path
William A. can you find the "MotherDuck ID" on the Vercel project page and share it here or via DM? I can take a look to see if the organization might be missing part of the configuration