Object structure of view cluster & not checked.

What causes this issue?

The View cluster object structure was not tested for correctness
because of serious View cluster definition errors.

System Response

The View cluster was not activated.

How to fix this error?

Correct the reported errors and re-activate the View cluster.
The View cluster activation log contains a detailed list of errors
under the menu path "View -> Display messages -> All."

Error message extract from SAP system. Copyright SAP SE.