No external product code for internal code &1 (ext. tax system &2)

What causes this issue?

Product codes are also used for tax determination for the external tax
system &V1&.
However, no external code is specified for internal product code &V2&
(entered in tax code &V3& in tax calculation schema &V4&).

System Response

The system cannot continue processing.

How to fix this error?

Check FI customizing for the tax indicator specified.
<DS:TRAN.FTXP>Maintain tax code</>

Error message extract from SAP system. Copyright SAP SE.