After DECADES of successfully syncing my Discover Card account with Quicken, I am suddenly getting CC-503 errors here too!!
I can sign into the bank website so I know I have the correct login/password, but when I tried to re-add the account using the same credentials I get this:
I now have EIGHT accounts that no longer sync with Quicken. It started with Nordstrom and that's been since November 2024.