Yes, I see it now too. It was noted as an issue on the mobileorg-android github site here over a month ago:
It looks like Dropbox shut down handling their v1 API and it would take updating mobileorg-android (and the iOS one) to the new v2. I looked at it a bit but it would take a while to understand the changes needed to try to make them. I was hoping the author would be able to do something but nothing so far. I believe Dropbox announced this would be happening many months ago (a year?) so it's not like there was no warning.
If you've got ssh working then you're probably OK. I don't have a ssh server to use so I may try to look into it again if I get time, but I still hope the author will be able to do something about it as I'm sure they could do it much faster.