Item: & - goods/service number & not entered

What causes this issue?

A G/L account could not be determined from the invoice specifications
for the specified item.
The goods/service number via which the G/L account is determined is not
entered in Financial Accounting customizing.
The goods/service number is taken from the intermediate document type
field
- INV_ID01: EDI_Z51-MATNR or
- INVOIC01: E1EDP19-IDTNR (for E1EDP19-QUALF = "002 - Vendor's
material number").
If the intermediate document type field is not transferred, the access
is carried out with the value "*".
If the surcharges/discounts at header level are to be displayed
separately, the special value "+" (surcharge) or "-" (discount) is set
as the goods/service number.

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?

Maintain the missing goods/service number and a G/L account to be
posted to within Financial Accounting customizing.
<DS:TRAN.OBCB>Proceed</>
Note:
Determination of the G/L account via configuration can be replaced by a
so-called customer function. If this is the case in your system, the
error message means that determination of the G/L account via the
customer function was unsuccessful.

Error message extract from SAP system. Copyright SAP SE.