Let's use DropBox as one example. I have the App Key and App Secret from the DropBox App Console. Using the Demo, when I click Connect the first time after creating the Application, I get a web page asking for permission to continue:
Before you connect this app... Make sure that you know and trust this developer.
Cancel / Continue
Clicking Continue then presents this web page:
MealService would like to View basic information about your Dropbox account.
Cancel / Allow
Clicking Allow then displays this page:
Application successfully authorized
So, I believe that I am connecting. In fact, the DropBox App Console shows the number of API calls. However, in the Demo, the list of files never refreshes. The log shows "Get Folder List" several times.