Go to Settings > Permalinks and save the new settings. After that, the link should work.
Sorry still confused… what permalink setting does the plugin expect to finish the handshake with the Dropbox app authorization successfully?
The permalink structure setting does not seem to affect the missing re-directed file or directory link
All you need to do is save the permalinks as they are, and the changes should take effect immediately. What are your current permalink settings?
I had Permalinks set to plain (default). Only when I change and save (post names in my case) does the connection seem to succeed.
When I select add external files in Media Library and select DropBox as the source I get an empty screen with a title Choose file(s) from your DropBox. Shouldn’t I see a list of files/subfolders ?