Message SAP WS532 - Release of document &1 not possible, active follow-on document items

Diagnosis
You want to release a document to accounting. At least one item in thedocument is already set in a follow-on document and is still active.

System Response
The system cannot release the document to accounting.

Procedure
If you want to release the current document, first ensure that thedocument contains only active items.
You can also set the active document items in a follow-on document andthen release this follow-on document.