Can’t create account through Dropbox

I’ve got everything setup, but STILL getting this message.
Does this mean MY WordPress installation has run out of app users? Or YOUR app has run out?

This app has reached its user limit. Contact the app developer and ask them to use the Dropbox API App Console to increase their app’s user limit.

I need to resolve this, or get a refund for the costs…

The page I need help with: [log in to see the link]