Do not mix direct tax and non-direct tax &1

What causes this issue?

You are using the same tax code in a document to post direct taxes, for
example, for import and export, and to process tax-relevant tax rows.
For more information, see SAP Note 869540. This is not recommended.
However, you can switch off this message by using SM30, V_T100C.

The system issues an error message and will not allow you to continue with this transaction until the error is resolved.

System Response

How to fix this error?

Procedure for System Administrators

Error message extract from SAP system. Copyright SAP SE.