We resolved this. I think a section about adding the Adobe URL to the approved Redirect URIs in the Dropbox app will help people with the configuration. Without going too deep into the Dropbox app setup. https://experience.adobe.com List any Dropbox source folder name restrictions, such as no spaces...

Krati, any suggestions?

I added the reply with screen shots.

I did both app types in Dropbox, scoped app and scoped app (app folder). Our agency partner was unable to provide the connection, so I created a test account. The account syncs through assets view but no assets come in and the Dry Run shows no assets. 

I made the connection to Dropbox but the assets inside the mapped folder aren't importing. Is this a configuration on the Dropbox app side? Thanks.