Dropbox OAuth authentication confirmation pages

That's the expected behavior for apps in development status. Apps in production status do not get that first confirmation. If your app needs production status, refer to the information here on how to request that.

The second confirmation is expected for apps in both development and production status. Note that the app authorization flow only needs to be done once per account though. You can request long-term access if needed. Refer to the OAuth Guide, authorization documentation, and this blog post for more information. Also, in some (but not all) cases where the user has already authorized the app and redirect URI is used, they may be automatically redirected through the second confirmation.