Purchase order type '&' is not defined

What causes this issue?

Purchase order type &V1& is not allowed.
INCLUDE 'NA_NO_PROCESSING_2' OBJECT DOKU ID TX LANGUAGE E


&WHAT_TO_DO
Check in table T176T whether an entry for purchase order type &V1&
exists in the language in which you have logged on. If the entry is
missing, enter it in the logon language.
If you do not have the authorization to do this, contact your system
administrator.

Error message extract from SAP system. Copyright SAP SE.