How To Fix VP864 - External number assignment not allowed

SAP Error Message - Details

• Message type: E = Error

• Message class: VP - Vertriebsbelegpartner

• Message number: 864

• Message text: External number assignment not allowed

What causes this issue?

You want to assign an external document number even though an indicator
for external number assignment has not been set for the number range
allocated to this document type.

How to fix this error?

If external number assignment should be allowed for this document type,
you must set an indicator for external number assignment for the number
range allocated. Otherwise you can delete the number of the number
range for external number assignment in the document type so that the
field no longer accepts input for external number assignment in the
document.
INCLUDE 'NA_CUST_MAINTAIN_3' OBJECT DOKU ID TX LANGUAGE E
Set indicator:

Error message extract from SAP system. Copyright SAP SE.