Enter the same tax code types (input or output) for old and new code

What causes this issue?

You cannot save an entry with empty error code if the old code and the
new code have different tax code types (input or output).
Leaving the <LS>Error Code</> field empty indicates that you want to
change the default target tax code of either an incoming invoice (except
for incoming 0% invoices) or an outgoing invoice.

System Response

The system does not save the entry.

How to fix this error?

If you enter an input tax code in the <LS>Old Code</> field, enter an
input tax code also in the<LS> New Code</> field.
If you enter an output tax code in the <LS>Old Code</> field, enter an
output tax code also in the <LS>New Code</> field.

Procedure for System Administrators

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

Error message extract from SAP system. Copyright SAP SE.