Update: I just checked, and transaction downloads work fine in Banktivity 7 (sorry; between this issue and stock updates no longer working, I'm looking at other software). So the problem definitely seems to be specific to Moneydance.
Open the Help->Show Console. Clear the console and then try to download Citi Card. Copy the results to a word processor, replace your account number with XXX's or something obvious and then post the results. (remove any other sensitive info).
Having the console window open when you communicate with he bank seems to include more info on the actual transaction.