Can't toggle between manual and automatic for the download cache in an Open Data site when the 'Allow anonymous access to your organization's website' box is unchecked from the Data tab.
1. From the Organization settings, check the checkbox for 'Allow anonymous access to your organization's website'. 2. Click Save3. Add the ArcGIS for Service as an item to ArcGIS Online again. Toggling works for the download cache in <a href="https://hub.arcgis.com/admin/data" target="_blank">https://hub.arcgis.com/admin/data</a> for this newly added item.