Getting the above error with my Costco Visa card for the last several days.
Resetting my account to use EWC+ instead of DC fixed the issue. I think many financial institutions are moving away from DC for security reasons. At least that was the rationale given by B of A when they forced its users to switch connection methods and we lost the ability to do bill pay.
When I reset the Citi account, only Web Connect and Express Web Connect + were listed as options - Direct Connect was not presented as an option.