There's a possibility that, if your password contains special characters other
than A...Z, a...z, 0...9, Quicken may not accept that because the bank didn't request Quicken / Intuit to allow special characters in passwords. Try using passwords without special characters, not longer than 16 characters.
If that doesn't resolve the issue, I'd say it's time to call Quicken Support on the phone and request
help. Let them do a screen share session
with you to review a download log file on your computer, to determine the nature
of the problem and to figure out how to fix it.