I feel for you.
This should be dead easy.
That's exactly what I would like to achieve.
I thought I had all the possible boxes ticked and everything accounted for and then I get "Coupon code is XYZ not valid" in my shopping cart.
I see this question asked over and over, but no simple instructions or a process on how to resolve.
Unfortunately lots of expert speak that the majority cannot understand.
Anybody seen an instruction manual or quality tutorials for v1.9.2.1 or abouts?