API [Content] - "Unauthorized - Cannot authorize with this service"

Problem Overview

When you make an API call with a server-side authentication app, you receive the following error:

status":401,"code":"unauthorized","help_url":"http:\/\/developers.box.com\/docs\/#errors","message":"Unauthorized - Cannot authorize with this service"

Root Cause

The admin setting Disable unpublished apps by default is on, and your app hasn't been enabled.

To check this setting:

1. In the Admin Console's left pane, Apps
2. Click Custom Apps Tab 
3. Click Settings (gear icon) to verify whether Disable unpublished apps by default is enabled. If it is enabled, ensure you've added the application's API key - also known as client ID - using the plus icon to Add Platform App.

You or your admin can enable the app from that list. It should read "Authorized" and "Enabled" once complete.

If you're seeing this issue with an OAuth 2.0 standard (client-side) authentication app, see the resolution steps here.