Unable to add data from Portal for ArcGIS to ArcGIS Online

Description

When attempting to add data or map service from ArcGIS Enterprise to ArcGIS Online using the service URL, the process fails. Depending on the type of data used, the following errors may be returned:

Error:   
There was an error while adding this item.

Error:   
The layer cannot be added to the map.

Cause

The service URL for the data or map service uses an internal URL. This is because ArcGIS Web Adaptor is configured with an internal network URL.

Solution or Workaround

Reconfigure the ArcGIS Web Adaptor URL to be publicly accessible, and then readd the data or map service to ArcGIS Online with the new service URL. Refer to ArcGIS Enterprise: Configuring the Web Adaptor from the configuration web page for instructions.