I need my shipping to be as follows:

1. Free for orders to be delivered in Portugal
2. In alternative, TNT courier service for orders delivered in Portugal, with a 5€ cost
3. 5€ cost for all orders from abroad. No TNT available for these

So, I setup the Flat Rate Clone and named it TNT, and it worked for all shipping addresses when I configured it like this:

Flat Rate Clone

Enable Flat Shipping
True

Shipping Cost
5.00

Tax Class
--none--

Tax Basis
Shipping

Shipping Zone
--none--

Sort Order
0

However, when I changed the shipping zone to “Portugal”, or any other for that matter, the module became “yellow” and ceased to appear.
I tried the same in the regular Flat Rate module and it also became yellow when I defined a zone...
What can I be doing wrong?