The hierarchy contains multiple root node (Only one is displayed)

What causes this issue?

The hierarchy contains multiple root nodes.

System Response

Because hierarchies can only be displayed with one root node in the
hierarchy simulation, the system only displays the first root node with
its subtree. However, the correctness check is only carried out for the
whole hierarchy.

How to fix this error?

If errors occur in the parts of the hierarchy that are not displayed,
use the preview dialog, in which the system displays the whole
hierarchy in a list, to analyze the error. If you cannot see the error
in this way, individually load the root nodes with their subtrees so
that you can analyze errors in the individual subtrees.

Procedure for System Administrators

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

Error message extract from SAP system. Copyright SAP SE.