Thank you, Cory and Joe.
We are investigating this issue, but so far it does looks like Dropbox has made changes on their side.
I will share an update here when I have more information.
Replicated in the Xerox lab as well, it functions as if you never typed into the 2 fields at all.
This seems to be a returning issue, but Dropbox will not signin. I can enter the user and the password, but the signin button and the signin to Google are both faded. Was able to sign into G Drive and One Drive with no issue. Tried this on a WorkCentre 78xx, an AltaLink C80xx and a VersaLink C405.