How To Fix FKKINV420 - Preliminary invoice &1 cannot be invoiced with other documents

FKKINV420 - Overview

• Message type: E = Error

• Message class: FKKINV - Invoicing in Contract Accounts Receivable and Payable

• Message number: 420

• Message text: Preliminary invoice &1 cannot be invoiced with other documents

What causes this issue?

It is not possible to process <DS:DE.INV_PRELIMINARY_KK>preliminary
invoice</> &v1& in an invoicing unit with other source documents or
other preliminary invoices.

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?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.

FKKINV420 - Details

• The SAP error message FKKINV420 indicates that a preliminary invoice (also known as a pro forma invoice) cannot be processed together with other documents in the invoicing process. This error typically arises in the context of the SAP Contract Accounts Receivable and Payable (FI-CA) module, which is used for managing customer accounts and billing processes.
  
  Cause:
  The error can occur due to several reasons:
  
  Document Type Restrictions: The system may have restrictions on processing preliminary invoices with certain document types. For example, you may not be able to combine a preliminary invoice with a final invoice or other types of billing documents.
  Invoicing Configuration: The configuration settings in the SAP system may not allow for the combination of preliminary invoices with other documents. This could be due to settings in the billing type or document flow.
  Incomplete Data: There may be missing or incorrect data in the preliminary invoice or the other documents that are