I'm able to successfully list folder and contents when my dropbox developer app has full access, however, when I'm using scoped access only to a specific folder, it fails.
Now when I switch to scoped access to a specific folder I'm running into errors. This request should fail since the app does not have access to the folder.
Now when I put in the right folder path, I'm still getting the same error.
It looks like you're using the App Folder permission. This will root all your paths relative to that app folder; your app will not be able to see outside of it.
For example, if the user sees the file as "/Apps/AppFolderAccess/myfile.txt", your app will see it as "/myfile.txt". By setting your path to /Apps/AppFolderAccess, it is effectively resolving as /Apps/AppFolderAccess/Apps/AppFolderAccess - which is not found.
If your application needs to see content outside its app folder, you should select full access.