The required equipment hierarchy contains inconsistencies

What causes this issue?

The <GL:equipment_hierarchy>equipment hierarchy</> that you are trying
to create contains inconsistencies, for example
recursiveness.

System Response

INCLUDE 'KEINE-VERARBEITUNG' OBJECT DOKU ID TX LANGUAGE E

How to fix this error?

Proceed as follows:
Reverse your entries.
Display the hierarchy in its present form by means of the structure
overview.
Correct the inconsistencies.
Continue structuring the equipment hierarchy.
RESET N1

Error message extract from SAP system. Copyright SAP SE.