The server at <Administration URL> returned an error. Could not find resource or operation 'admin' on the system

Error Message

In ArcGIS Enterprise, when federating a server site to the portal, the process fails and returns the error message below:

Error:
Error: The server at <Administration URL> returned an error. Could not find resource or operation 'admin' on the system.

Cause

The system attempts to federate the server using an incorrect administration URL that contains the /admin path, for example:

https://machineName.domainName:6443/arcgis/admin

The /admin path points to the ArcGIS Server Administrator Directory, which is invalid for federation and causes the process to fail.

Solution or Workaround

Note:
This workflow must be performed by an administrator.

1. Log in to the ArcGIS Portal Directory with an administrator account.
2. On the ArcGIS Portal Directory page, click the Org ID link.
3. At the bottom of the page, for Child Resources, click Servers.
4. Click the Server Id link.

5. For Supported Operations, click Update Server.
6. In the URL text box, specify the correct administration URL in the format below.

https://machineName.domainName:6443/arcgis

7. Click Update.