SD document & is not in the database or has been archived

What causes this issue?

You get this message in the following situations:
The SD document you have specified does not exist. The document might
have been archived.
The system did not find a document header (VBAK) for an individual sales
requirement record (VBBE).
An inconsistency has occurred in the ERP system.

System Response

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

How to fix this error?

If the error occurs during the initial data provision in APO, there is
an inconsistency between the requirements and the SD documents in the
ERP system. You can use report SDRQCR21 to correct the inconsistency.

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.