Update 11/26: This issue is now resolved and your Citibank Accounts should now be updating successfully.
We are aware of an issue with updating Citibank accounts, and our aggregation team is working on a resolution. While we do not currently have an ETA for a fix for this issue, it is being worked on with very high priority.
We will update this page as soon as we have an update. We appreciate your patience and understanding throughout this matter.