In Oracle Cloud Fusion, no value sets in the tax classification at AP invoice lines, why? The tax cl

In Oracle Application CLoud Fusion, I defined a tax rate DC20.0.

I added it in the lookup types ZX_INPUT_CLASSIFICATIONS and ZX_WEB_EXP_TAX_CLASSIFICATIONS.
On a supplier address, at the transaction tax, I put the tax classification code to DC20.0.

For this supplier I created an invoice => the tax classification at the invoice line was not defaulted. I tried to manually update the tax classification code with the DC20.0 => error message Invalid value. The value sets for the tax classification code at the AP invoice line is empty, why?