Please Check Slip Postings.
The matter may be in the Rejected or Draft Section.
Do the following:
Rejected Slip
Select Slip, then Delete.
Draft Slip
Select slip - Amend,
Untick the Draft box.
Save, this will add it to the To Post section.
Select Reject Button.
Select Reject and Delete
Use Matter Archive to archive the case again.
If another error message is shown,
Please raise a new case online and reference the title of this article.