Planning object &1 not found for item &2/&3

What causes this issue?

The planning object &v1& for item &v2&/&v3& was not found.
The planning object (location and/or account assignment) was changed
after backorder processing was executed.

System Response

This item is not displayed in the backorder processing results list.

How to fix this error?

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

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.