Number range 01 for HRPP_PDOC is not internal

What causes this issue?

The number range for allocating document numbers is flagged as
external. However, when creating the documents the document number must
be allocated by the SAP system and not by the user. As a result, no
document number could be allocated, and consequently, no document can
be created.


&WHAT_TO_DO6
Flag the number range HRPP-PDOC as internal.

Error message extract from SAP system. Copyright SAP SE.